I know I'm human. And if you were all these Things, then you'd all just attack me now, so some of you are still human.A group of people are invited to attend a get-together, usually held at an Old, Dark House often in the middle of the lush country side or (more recently) on someone's Private Island, by a mysterious and/or eccentric host. Suddenly one of the guests (or even the host) is murdered and circumstances prevent the others from leaving, usually a heavy storm or a cut bridge, or even both. Our heroes soon learn that one of their party is actually some manner of villain (typically The Mole, though a random escaped criminal is not unheard of), but, for various contrived reasons, that's all the information they're going to get. So it's up to them to work out which of their supposed colleagues is really The Mole before he can kill them all. And you can't trust anyone until you do. Luckily, however, there's (usually) only one mole involved. Often results in everyone being Locked in a Room. This can be self-imposed, as our heroes can't chance The Mole reporting back to headquarters, but a Genre Savvy enough character may force this upon everybody, which will usually raise everybody's tension. Circumstances will always contrive to prevent our heroes from getting in touch with the outside world to find out who The Mole is, which may range from the aforementioned storm knocking out the telephone poles, to someone cutting the telephone lines, to outright smashing all the phones to pieces. Accusations are hurled, secrets are uncovered and more murders are committed as the Dwindling Party tries to determine who is the murderer in their midst. General outcomes of this plot:
— R.J. MacReady, The Thing (1982)
- A: One person will seem to actively hinder the investigation. He'll drop the radio, breaking it just before a description of The Mole is broadcast. He'll have a panic attack at a critical moment endangering the group. He'll be suspiciously uninformed about whatever his job is supposed to be. This person is never The Mole. He's just an idiot. (See Hanlon's Razor.)
- B: One person knows his job well, but he's a little high-strung. He accuses a lot of people of being The Mole on shaky grounds. If it doesn't turn out that he's the Mole (which is a little too obvious, and therefore rare), odds are the real Mole's going to kill him.
- C: One person is very competent and helpful. He'll even have some extra skills that are handy for just the room in which they are locked. He might even find clues as to The Mole's identity. At some point, he'll save the hero's life. He's The Mole, and he's really very good at it.
- D: The idiotic Red Herring Mole turns out to be a spy for the good guys. He's been keeping it a secret since, like everyone else, he's not entirely sure that the mole isn't one of the heroes. His apparent incompetence is really Obfuscating Stupidity, and he's trying to goad the real Mole into tipping his hand.
- E: There's a second mole—perhaps even one that the first mole doesn't know about.
- F: None of them are The Mole: the initial message was a fabrication by the bad guys to make the heroes turn on each other.
- G: None of them are The Mole: the hero has been hypnotized to act as mole without even his own knowledge, or is simply an Unreliable Narrator.
- H: The Mole successfully frames someone else.
- I: No one is The Mole: for whatever reason, everyone's paranoia has spiraled completely out of control, causing them to attack each other on otherwise flimsy pretexts or misinterpreted accidents. Or the host, with the help of his staff and/or associates, faked it all to "entertain" his guest.
- J: Someone dies early, but they Never Found the Body, or it was mutilated too badly to be positively identified: they are probably the Mole.
- K: No one is The Mole; the plot fits the Dwindling Party twist, wherein the villain is someone else who simply kills most of the main characters, one by one and usually in a extremely brutal and sometimes grotesque manner. Perhaps the villain is a demented, deeply troubled individual, or is a stalker who enjoys killing; maybe he is a crime lord who fears being caught (and his method(s) of murder and carrying the killings out is used to put fear in others and/or intimidate the authorities)...or he is simply the face of evil (who also hopes to intimidate the heroes and scare off the authorities). Once the original gang is whittled down to just two or (at most) three, the villain is finally defeated; either the bad guy is killed, usually by falling into one of his own traps or another character—often but not always one thought to be dead—arriving to defeat him, the remaining protagonists are able to beat down the villain and subdue him until the authorities arrive to arrest him; or (most commonly on TV crime/action shows) the title character arriving Just in Time before the villain kills the last remaining members of the group.
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Anime and Manga
- In Episode 5 of Azumanga Daioh, Osaka imagines one of these happening at Chiyo's summer home:
Osaka: And then it turns out...I'm the killer!Yomi: Why do you get to be the killer?
- In the Lone Island Syndrome episodes of Haruhi Suzumiya the SOS Brigade goes on a club field trip to an island mansion specifically set up to stage a murder mystery like this, in order to stop Haruhi from generating one herself (though it's left ambiguous at the end whether or not she's already created an external killer).
- The first Gall Force does this without the murders. Each cast member is offed by differing circumstances as they try to make their way to the planet Chaos. The mole was Catty, but she was only trying to arrange for one of the others to get a Face Full of Alien Wing-Wong in the name of galactic peace, and didn't actually try killing anyone. She sacrifices herself halfway through to let the other survivors get to an escape pod. A self-parody short of the entire series is even titled Ten Little Gall Force.
- In volume 30 of Detective Conan, Captain Ersatzes of famous detectives were invited to an abandoned mansion and die off one by one. Only one of them actually died. The rest faked their deaths once they deduced who the real killer was in order to Pull the Thread on her.
- Moto Hagio's They Were Eleven has this happening during a survival test where ten students are stranded on a derelict spaceship...so why are there eleven of them? Everyone knows that one of them shouldn't be there as accidents keep happening, and the hero has the additional problem of fitting the "competent and helpful" rule of Mole detection above—as the other students begin to notice. Everybody Lives. The extra examinee was an instructor sent in as The Mole to cause trouble and force the group to quit the test, as a Secret Test of Character for all of them; things got out of his control. The hero's suspicious knowledge of the ship was because he was unknowingly a survivor of the disaster that originally destroyed it.
- One arc of the manga Black Butler follows this trope's description to the letter, complete with large, dark mansion, gathering of wealthy guests, and the raging storm that means no one gets to go home. (And Ciel is most definitely fitting enough for the role of "mysterious host".) It turns out to be some bizarre, mind-boggling combination of E and I and involving one of the "victims" faking his own death.
- Urusei Yatsura had an anime only episode where the group was killed off one by one till only Ataru was left In the end, it turned out the murders and complicated reveal of a killer with Ataru's face were a complicated plan by the perfectly unharmed victims to "Fix" Ataru's personality. The ending makes it pretty clear that Ataru saw through it at some point and proved to be a better actor than they had realized.
- In a chapter of Franken Fran, Fran is invited by former patients for a party in a remote location. Soon, they are attacked one by one—hopefully, Fran can save them. This being Franken Fran, the truth is far more disturbing than expected. Even Fran finds it disturbing.
- The answer? The victims are doing it to themselves because they get off on Fran operating on them.
- One of the filler arcs from Bleach featured this. Ichigo's group of friends have to get through a series of games, one of which involves a member of their group being kidnapped and replaced by an shapeshifter. It turns out to be Chad.
- The manga Doubt was a version of this, but with hypnosis—the real killer hypnotizes another and has her confess, then escapes.
- The sequel/spinoff, Judge, does this as well.
- The entire premise of the board game Clue, as well as The Movie based on it. The film involved a group of guests with questionable pasts being locked inside a mansion trying to figure out who killed Mr. Boddy. Every single one of them had a motive to kill him, and things aren't helped when the rest of the mansion's staff begins falling like flies...
- The board game didn't initially include the element of the suspects being killed, but later releases did, adding a deck of cards that included eight clock cards: once the first seven had been drawn (and taken out of the deck), whoever drew the eighth card was killed by the murderer (presumably if the killed character is actually the murderer, they just faked their deaths instead) and the card was then returned to the deck.
- Parodied in the board game Kill Doctor Lucky, by Cheapass games, the objective of which is to be the first to bump off the good Doctor. The players all despise Doctor Lucky, and have been invited to his country mansion for the weekend. In the words of the game "There's a howling storm outside, it's midnight, and someone just shut off the lights..."
- "Ten Little Injuns" and numerous adaptations. The original "Ten Little Injuns" began as a minstrel song written by Septimus Winner in 1868, and describes a group of 10 Native Americans (here called by the derogatory term "injun") and, as different events happen—most of them dying of various circumstances—eventually decreasing down to one. The lone survivor ends up married. Various adaptations involve anthropomorphic animals (usually for family-friendly children's adaptations, although several of the original 10 still die or disappear of ambiguous circumstances), teddy bears and dolls, people (most often soldiers) and—in the racial sense—minorities.
- Mafia-style games often run into this, as the town's objective is to hunt out the "mafia" from their midst. Many is the game where a last lynch leaves two town players or a last kill means the sole surviving mafia member.
- Parodied/subverted in a Doctor Who Magazine comic strip, in which a group of minor villains that the Doctor has previously defeated gather together in a deserted space-station to plan a final attack that will finish him once and for all. One of them dies horribly, and as the others begin dying one by one afterward, it seems (to them, anyway) as if the Doctor has infiltrated their midst in disguise and is picking them off one by one. Finally, the last couple—paranoid that either one of them could be the Doctor in disguise—kill each other...and at that point, the Doctor arrives, not recognizing any of them. Turns out the first death was just an accident with a faulty machine and the other deaths were just everyone picking each other off out of sheer paranoia.
- Played straight in an earlier Eighth Doctor strip.
- Happens to the Club of Heroes in "The Black Glove" arc in Batman.
- In the first Blackhawk comic published by DC, one of the stories concerned the Blackhawks being mysteriously incapacitated one by one—not killed, but sidelined, hospitalized for a day or two. It turned out to be a publicity stunt by a movie studio, intended to drum up interest in their upcoming movie "Ten Little Indians".
- This trope is the most popular mystery outline for any fanfiction category (there are even fanfictions under the trope namer's category using original characters for the plot) thus making any possibility of listing all examples ludicrous.
- Devil: In an elevator. One of them is the Devil.
- House of Wax (2005): The 2005 version features six college-age students traveling to the big game, when they stop in a rural Louisiana town to camp for the night. One by one, each of the six are targeted by a pair of brothers running the town's museum...and four of them are killed in the most violent of manners. (The two survivors later discover that most of the town's inhabitants have been killed by the brothers through the years, and have to escape the town before they're next.)
- Murder by Death is the Affectionate Parody of the genre; here, the guests are thinly-disguised versions of famous fictional detectives. The trope is subverted when it turns out the villain isn't really interested in killing them off, but in embarrassing them instead.
- Alien³, which has been described as "And Then There Were None in outer space" by Entertainment Weekly, had the entire population of Fiorina 'Fury' 161, save for one prisoner (Morse), killed off by the xenomorph that had infiltrated the prison. This includes Ellen Ripley herself, who died as a combined result of the chestbursting chewing its way out of her, and a suicide dive into the prison's metalworks.
- April Fools' Day. There's even little dolls representing the guests, prompting one to say that it's "like something from Agatha Christie".
- By the end of The Ladykillers, the robbers have all killed one another except the Professor, who is struck on the head by a railway semaphore. Little Mrs Wilberforce is left with all the "lolly".
- The film adaptation of Clue was essentially a gigantic parody of this trope.
- The Bollywood movie Gumnaam is an uncredited remake of And Then There Were None.
- The bank robbery in The Dark Knight might be considered a high-speed variant of this, as one robber after another kills an accomplice, then is killed in turn. Unique in that it takes place at the scene of another crime in progress, and the guy who figures out what's going on ("Let me guess: you're supposed to kill me?") is immediately killed.
- The '80s version of The Thing (1982)—and the short story both versions were based on, "Who Goes There?"—both combined this trope with The Virus.
- Another alien-invasion movie example: The Faculty; the humans who have not (yet) been taken over by alien parasites regard each other with suspicion and must figure out who in their number has fallen under alien control...but more than that, they must determine which person has actually been an alien all along. Not really surprisingly, the one who is an alien rather than an alien-controlled human is the "new girl", who has been giving the other students a Back Story they've had to take on faith, rather than having a known history in their community.
- Identity is a variation of this. 10 strangers meet in a remote hotel, where they start getting killed one by one by a killer, who is presumably one of them. At first the trope seems to be played straight, as the helpful authority figure cop is revealed to really be a criminal and a killer. However, at the end, it's revealed that the killer who was actually killing the guests was the little boy. This makes sense because the characters are all personalities inside the mind of a serial killer with multiple personality disorder; the little boy is the murderous personality, representing the abuse the killer experienced as a child.
- D-Tox was a film with this premise, starring Sylvester Stallone. Stallone was one of 9 cops being treated for psychological problems at a remote ranch in snowy Wyoming. However, one of the other patients was actually a serial killer who targets cops, having killed the real patient and assumed his identity. The real killer turned out to be the character who was most apparently helpful and mature (as opposed to the cowardly guy or the violent alcoholic).
- Mindhunters was another film with this premise, about several FBI students being trained as criminal profilers at a remote training facility. One of them is actually a serial killer killing the other characters off one by one. The killer turns out to be the heroic, helpful, supportive Alpha Male of the group.
- Reservoir Dogs, in which one of the robbers may (or may not) be setting the others up.
- The Usual Suspects, which has basically the same premise, although it's told in flashback by the one survivor who's afraid that the killer might come after him too.
- Where Eagles Dare has not one, but three of these. Four if you count the Colonel.
- Fantastic Voyage establishes that at least one of the crew of the Proteus may be a Soviet agent sent to finish the assassination attempt on the scientist the mission is meant to cure. Violating the first rule of mole detection above, the character played by a sweaty, nervous Donald Pleasence who tries to open the hatch of a submerged submarine as soon as they're shrunk is the traitor (Or just a claustrophobic man in a cramped sub who went off the deep end trying to get out--the movie never says for sure.)
- Before the Liam Neeson flick of the same title, a film called Unknown combined this with Easy Amnesia and Paranoia Fuel. Several men, some of them kidnappers and others, their kidnappees, wake up with no memories and find themselves locked in a warehouse, having all been overcome by an accidentally-released toxic gas. A brief phone call from the kidnappers' accomplices reveals that more thugs will arrive soon, and presumably kill the ones who aren't on their side, but none of the trapped men know if they're the culprits or the victims...
- A very straight example in the first Eko Eko Azarak Japanese film, where students are magically trapped inside a school and being killed off one by one.
- Played straight in Das indische Tuch (1963), released in English as "The Frightened Lady".
- Saw 2 has a group of apparent strangers finding themselves locked in an abandoned house, which is obviously full of Jigsaw's traps. They soon begin to learn that something links them all together...
- In Sisters of Death, there are two moles: The one responsible for Liz Clyburn's death seven years earlier and a witness who knew the gun had real bullets in it, but stayed silent. The latter turns out to by Sylvia. The former, Judy claimed that Liz switched the rounds herself to commit suicide. Judy lied.
- Triangle appears to be one of these, but its "six victims on a haunted cruise ship" beginning gets subverted hard.
- The Trope Codifier: Agatha Christie's And Then There Were None, a.k.a. 10 Little Indians. The Mole is Justice Wargrave.
- The Strugatsky Brothers' Hotel of the dead alpinist seems to start this way...and then things get weird.
- The novel The Man Who Tried To Get Away by Stephen Donaldson is one big heavily-lampshaded exercise in the trope. Private eye Brew Axbrewder is running short on cash and needs to lie low after treading on the toes of a local crime boss, so he reluctantly agrees to be a consultant and participant for a murder mystery vacation in a lodge out in the woods. He (predictably) hates every minute of the contrived And Then There Were None event, right up until one of the participants gets killed for real. And someone has cut the phone lines. And a blizzard has blocked the only road back to town. Axbrewder and his partner assume that the crime boss has found out where he is and sent someone to take out Axbrewder and kill all the witnesses, but he's only half right. The crime boss does have a hitman at the event (the maintenance man, who gets sent out to try and walk back to town, turns out to be working for him), but neither our hero or the detective know that two of the guests are actually violent psychopaths who booked into this vacation for kicks, and it's they rather than the hitman who kill most of the other guests.
- Parodied in Anthony Horowitz's novella I Know What You Did Last Wednesday. The twist is that the killer isn't actually on the island. He set everything up before hand and is controlling it remotely.
- Played with in the teen horror novel Class Trip by Bebe Faas Rice. The Ten Little Murder Victims plot is related in first person by one of the characters. Eventually there's just two of them left, and the police are on the way. The narrator then reveals that ''she'' was the killer all along. However, before she can kill the last remaining character, he reveals that he tape recorded her Engineered Public Confession even though he didn't intend to. She starts crying as the rescuers arrive as she realizes she is caught.
- The book and movie version of The Ruins has this trope as a central plot point. In the book, all of the characters are killed by a man eating, parastic vine.
- Several of Simon R. Green's Hawk And Fisher stories use this trope. His Secret Histories novel The Spy Who Haunted Me has a variant that plays out among spies held together in a group by the terms of their mission, rather than by geographic isolation.
- A variation happens in Murder on the Leviathan, which was intended as a tribute to Agatha Christie; what makes it unusual is that this situation came about when a detective looking for a murderer on a luxury liner had his chief suspects assigned rooms in the same salon. And then one of them was killed.
- Ten Little Wizards, a Lord Darcy novel, is an homage to Christie's version. A subversion, in that the killer's countdown doesn't make it to "none", and the apparent killing spree is an Evil Plan by Polish spies.
- Ripper is Michael Slade's take on this trope, with the added twist that the guests are all mystery writers and there are two killers working together, not just one.
- Also, because The Mole kills with pre-rigged death traps, even figuring out who it is won't guarantee safety: the traps will still be lethal.
- In the Star Trek novel Kobiyashi Maru this was a training scenario for Starfleet cadets. Several dozen cadets were dropped on an abandoned moonbase, and told that one of them was The Mole. Their teachers then sat back and watched what the cadets did. Typical behavior was to band together into small groups, and end up fighting against other groups because one of them could be The Mole. Chekhov's solution was to simply kill EVERYONE (at the end of the training, all his victims assumed he was the Mole. He thought he was the winner. The teachers explained he was simply a very skilled assassin (and a bit of an idiot)). Turns out there was no Mole, the scenario was designed to emphasize the dangers of distrust and paranoia. He was then told that his hero, a young captain named Kirk, had come up with a working solution; he invited all groups to join his, but the condition for joining was that everyone would be disarmed. The exception were two guards selected by Kirk; if one of them happened to be The Mole, the other could just shoot the guy.
- In Maurice Leblanc's first published Arsène Lupin short story, L'arrestation d'Arsène Lupin, the passengers of a transatlantic liner learn by telegram that the famed Gentleman Thief is travelling in first class under an assumed name. All they know is he is blond and his fake name begins with R. The story deals with the idle young nobility on board trying to unmask him from those clues while various precious objects are stolen around them ; until the ship arrives and Lupin is revealed as the narrator, who was not blond and whose name did not begin with R, but who planted false clues to mislead the police.
- Used to some extent in Dune, with a letter throwing transparently false suspicion on Jessica. No one in House Atreides suspects Yueh of being The Mole at all, though he's already been identified as such in the narrative (it's presented as a mind-blowing revelation in-universe due to his loyalty conditioning).
- A major plot thread in the second Mistborn book-it appears for much of the book that one of the main characters has been replaced by a kandra, a creature that can consume a corpse then animate it and imitate the person in question almost perfectly. Despite assistance from her own kandra, it takes Vin most of the book to figure out who it was. As was stated on the main Mistborn page, The Reveal is quite brilliant.
- Subverted in The Dresden Files book Dead Beat, where Harry quickly and decisively identifies the current body of the Corpsetaker within seconds of his/her/its body-hopping.
- Something like this plays out in Kitty's House of Horrors. It's all a subversion. The panicky, incompetent, suspiciously underinformed person isn't the mole, but survives anyway. The competent but high-strung person who constantly accuses someone else of being the mole isn't the mole, and also survives. The helpful, amiable person with lots of useful abilities isn't the mole either. No one is. However, almost everyone besides those three and the narrator dies. Everyone in the house was an intended victim.
- Subverted in Jo Walton's Alternate History novel Farthing, which is set up as a classic country house murder mystery, then is revealed to actually be a political conspiracy.
- In L. Jagi Lamplighter's Prospero Regained, the Prosperos have been told they have an in-family traitor. One of the things they try to unearth while descending through Hell to rescue their father.
- A variation happens in A Dance with Dragons, the fifth installment of A Song of Ice and Fire. Roose Bolton and his allies, who are camped out in Winterfell, waiting for an enemy army to march to them, start suffering a string of murders in their ranks. Considering many in their own number hate each other's guts, there's at least one enemy agent undercover in the castle, and some of them have very good reasons to hate their liege lord, there's suspects galore.
- Oddly, while it's established mid way through book five that most of the murders were committed by Maynce Raydner and his spear-wives, they deny killing one victim in paticular (Little Walder Frey), meaning that there are at least two sets of independent murderers in Winterfell.
- In the teen suspense novel Deadly Detention, six students are sharing a detention when one by one they start disappearing. Everyone assumes that the detention teacher is the culprit. Everyone is wrong.
- The danger.com novel Shiver has this plot, set at a snowbound ski lodge with a group of teen actors who met online.
Live Action TV
- The Adventures of Brisco County, Jr. ("Bounty Hunters Convention").
- Bonanza: The 13th-season episode "The Rattlesnake Brigade", where the feared Dalton gang—on their way to prison—escapes and kidnaps Jamie and three of his buddies (a beautiful blonde and two other guys), and they plan to kill each of them, one by one, until the Cartwrights pay them a huge ransom and allow them free and undeterred access to Mexico. Indeed, one of the teens is shot and killed (during a botched escape attempt), but the Cartwrights arrive in time to stop the bad guys before any of the others are killed.
- The Facts of Life parodied the trope by having the victims killed in silly ways (Blair was killed by over-using hair spray, Natalie was strangled with a pair of fuzzy dice). In the end, it turned out to be All Just a Dream (a Dream Within a Dream, in fact).
- Game of Thrones: Jaqen H'ghar provokes this among the Lannisters at Harrenhal, and Tywin Lannister responds by torturing his own men in search of answers.
- Get Smart ("Hoo Done It").
- Land of the Giants did it twice, with the aptly named "Seven Little Indians" and later in "The Unsuspected."
- Remington Steele had at least one of these, with Steele referencing And Then There Were None and its signature plot twist: the sixth person to 'die' faked his death and was actually the murderer.
- Subversion: Homicide: Life on the Street once had a murder at an exclusive country club, that appeared to be one of these. After a Christiesque setup and a cutaway, the BPD detectives had the case closed by the commercial break.
- Harper's Island. With 29 deaths on screen and, out of the main cast, 4 survive.
- Stargate SG-1:
- The show features such an episode, only instead of a building, they are all stuck on the Alpha Site planet and unable to leave until the murderer is found. Tensions mount between the three races present, with the leaders under a lot of pressure to keep it from turning into a shootout. Accusations are flung around and the humans are stuck in the middle. The murderer turns out to be an invisible Ashrak, but the relationship between Earth and its two allies never quite recovers.
- The episode "Proving Ground" took the theme Up to Eleven. Given that the SGC's primary foes are Body Snatchers, they select new members through complex training exercises where Everyone Is a Suspect Mole. These exercises tend to be Total Party Kills. One particularly promising group that refuses to get their act together finds that their umpteenth test is Not a Game. It was a game with one of their own being a Reverse Mole whose job was to up the ante. When they knew it was all a game, they slacked off. When they thought it wasn't, they ended up distinguishing themselves under fire and becoming a quality team.
- In another episode, they knew who The Mole was, but it had an annoying tendency to Body Surf. That meant no one could be trusted—just because you weren't The Mole two minutes ago doesn't mean you're not The Mole now—and required some extreme measures to resolve.
- The Wild Wild West episodes "The Night of the Tottering Tontine" and "The Night of the Bleak Island".
- The Avengers episode "The Superlative Seven".
- A parody of the And Then There Were None theme was done on You Can't Do That on Television, where ten of Barth's burgers were used in place of Indians. The Mole and suspect was the second victim (it seemed) done to remove himself as a suspect. (The victims weren't actually murdered; they were kidnapped and later found Bound and Gagged in the lockers.)
- The episode "And Then There Were None" from CSI has the forensic team trying to locate a gang of casino robbers. The CSIs find that each gang member was killed by one of his or her partners, and end up following a trail of dead bodies to the last surviving member of the gang.
- Played with in an episode of Highlander, where Hugh Fitzcairn is killed and any one of his half-a-dozen or so houseguests could have done it. However, as he is immortal, he revives and spends the rest of the episode annoying MacLeod, who is trying to find the murderer without giving away the fact that he's still alive.
- Parodied in The Goodies episode "Daylight Robbery on the Orient Express".
- Mathnet (from Square One TV) did an episode like this that was both a parody (the villain turned out to be a court stenographer) and an homage.
- One Boy Meets World episode (Called "And Then There Were Shawn") features this plot, with the characters stuck in detention (caused by a quarrel between the main characters) and soon being killed by a mysterious murderer within the school, (including one by the name of Kenny. In the end, Shawn rips off the mask of the killer to reveal that it was him under the mask all along. Then it's revealed that it was all just a dream had by Shawn.
- Parodied in Frasier when the station is redoing an old radio drama. It was clearly supposed to be like this, but Niles (who was forced to take on multiple roles, including the murderer, at the last second) finally gets sick of Frasier's overdirecting and "kills" every other character in under a minute, before doing himself in cheerfully proclaiming that the secret of the mystery will die with him, leaving Frasier (as the detective) to desperately close the thing out.
- MacGyver: "The Invisible Killer". Just as Mac determines which of the Phoenix employees on his wilderness stress-relief retreat is an imposter, we find out that not one but two of them are really escaped convicts.
- The Twilight Zone (1959): "The Monsters Are Due On Maple Street". A street in a small town loses all power and use of their cars. Spurred on by a young boy's claims that this is a common comic book plot, they quickly suspect each other of being aliens. As riots break out, the audience learns that, no, none of the folks on Maple Street are aliens. The whole thing was set up by alien puppetmasters outside of town to trigger the riot, who comment on how easy conquering Earth this way is. Replace "aliens" with "terrorists" and "alien puppetmasters" with "US Army researchers", and you get the version used in the 2002 remake.
- First Wave did this numerous times and in every variation. They added the further complication that the hero himself was usually also an impostor in the group, and had to spend much of the episode convincing the others to trust him.
- War of the Worlds also did a number of variations on this. The most straightforward instance was "The Last Supper", complete with the undercover spy who initially appears to be a shoo-in for The Mole.
- The Mole implemented this concept as a Reality-based Game Show. Thought the show the contestants are faced with several challenges which, if completed successfully, earn money that goes to a global pot. However, as the name indicates, one of the contestants is a Mole hired by the producers to make sure they win as little money as possible. Contestants are eliminated via a quiz at the end of each episode that asks several bits of biographical information about the Mole: the person who gets the least amount of questions right is eliminated.
- Whodunnit also did this, although played much more straight here. The contestants were all ostensibly invited to the Reality TV Show Mansion by Giles, the show's host, at the killer's anonymous behest. Giles receives and passes on instructions from The Mole, who "kills" each episode's worst-performing player in some convoluted way, thus presenting a mystery for the contestants to figure out in the next airing.
- The second season of Who Wants to Be a Superhero? included such a challenge. Given that there were two actors planted amidst the first season contestants (both The Mole and a scheduled Face–Heel Turn), this was a believable threat for the heroes and the audience. But it turned out to be a false one; all the contestants were for real this time, and Stan just wanted to see if they'd go into witch-hunt mode.
- In the Star Trek: The Next Generation episode "Allegiance", Picard found himself in a similar situation to the Star Trek novel example, where he and three strangers are left in a cell with hints that one of them is working for their captors. In this case, not only was one of them the mole, but an impostor Picard was also placed on the Enterprise to run an experiment on the crew.
- In the season 6 opener of NCIS, we learn that Agent Lee is The Mole, but the team thinks it is Agent Langer, who Lee frames and then kills. Later, they figure it out and it ends in Redemption Equals Death.
- On WMAC Masters during a Dragon Star match between Hakim "The Machine" Alston and Ho Sung "Superstar" Pak someone wearing a ghost town ninja outfit eliminated both of them and the other masters figured out early on that one of them had to be the masked ninja. They suspected the maters who had not been seen that episode like Mike "Turbo" Bernardo and Ho Young "Star Warrior" Pak as the culprit and eventually put Star Warrior (who is the older brother of Superstar) on trial for it with Tiger Claw and Olympus acting as lawyers and Turbo as Judge. He was found not guilty after the glove Tracer clamed the mask ninja dropped did not fit (so they must acquit). It turns out the masked ninja was Warlock who had secretly joined the evil cult called Jukido and was trying to steal the Dragon Star
- Sanctuary has a particularly difficult one to solve. They do figure out who it is, but only the main characters survive until then.
- The story of the tail section survivors on Lost: Nathan is the Red Herring Mole. Goodwin is The Mole. Then there's Cindy and Libby, and we still don't know what was up with either of them. Prevailing fan speculation is that Libby was The Mole, too, but for a different organization.
- Haven has a nice twist on this. Some residents of Haven decide to throw Audrey a birthday party, since she's never had one. They decide to throw it on this nice old hotel out in the ocean on a small island with no cellphone reception. Well, long story short, the owner of the hotel had subtly dropped the suggestion that they should throw the party there. Turns out, the owner of the mansion is a chameleon-thing that kills people then turns into them, and he needs more people to change into. So one of the characters are no longer that character. Doesn't help that most of the people there are minor or new characters. Oh, and the ferry isn't coming back to get them until the end of the weekend, but there is a small boat that they ride away on.
- Nathan's dad shoots a hole in the boat, stating that if the chameleon gets back to the mainland, he'll escape and vanish forever, living out his days killing more and more people. Oh, he's not the chameleon.
- Since it's a birthday party, they decide to have everyone tell them what's in their gift, something chameleon wouldn't know. Here comes Nathan's turn. He says a blue sweater. Surprise: his present is actually a blue scarf. He had someone else buy the gift and comes to the conclusion that they must've thought that the scarf would've been a better gift than the sweater.
- And the chameleon is... Audrey. Yes, the main character is the chameleon. When the chameleon transformed into her, he took her form, but she didn't die, so she had to lock her in a chest hidden away in the mansion. Nathan had recently discovered that he could feel Audrey, when he can't feel anything else. He figured out who the chameleon was he couldn't feel "Audrey". To confirm, he kissed Audrey, still felt nothing, pushed her back, and calmly shoots her in the chest, killing the chameleon.
- Doctor Who:
- "The Curse of Peladon" has various delegates from alien civilisations who have come to the castle of Peladon in a storm. The Ice Warrior delegate nearly dies in an accident and the delegate from Arcturus is found dying with a vital part of his life support missing. Everyone gets increasingly paranoid and existing racial tensions flare up.
- "The Robots of Death". The twist being the killer is obvious hence the titles, likewise the mastermind behind reprograming them is revealed early on. The mystery is trying to figure out which of the crew, is them in disguise.
- "The End of the World" has a group of aliens from across the galaxy gather on a space station to witness the death of Earth, but somebody starts to kill those on board.
- "The Unicorn and the Wasp" has this setup as a given, considering that the famous historical figure of the episode is Agatha Christie herself.
- Referenced by title, and played with, in the Leverage episode "The 10 Li'l Grifters Job". The Mark invites all his favorite enemies to a murder mystery dinner party. Right after announcing that someone is about to die, the lights go off, and someone actually kills him. Nathan, realizing that he would be the prime suspect, has to figure out who actually committed the murder...while simultaneously trying to convince the rest of the guests that it's actually all part of the event.
- "Murder at Moorstones Manor" is the Ripping Yarns take on this trope.
- Xena: Warrior Princess had an episode based on this premise, aptly called "Ten Little Warlords".
- Whodunnit? (UK): In "Final Verdict", the eight surviving members of a jury who sentenced a killer to life imprisonment 20 years ago are invited to a dinner. Via tape recording, the killer reveals that he is one of the people attending the dinner in disguise, and that they have to find him before they all die.
- Miss Fisher's Murder Mysteries: In "Murder Under the Mistletoe", a Theme Serial Killer starts picking off the guests and staff of a Snowed-In chalet one by one.
- Sapphire and Steel parodies this in "Assignment Five". The apparent murders are actually a malevolent temporal force disposing of all the people who weren't alive at the time of events that are intended to suffer a Make Wrong What Once Went Right.
- Inside No. 9: ''"Private View" is based on this premise and takes place an art gallery, where all of the characters are told they have been hand-picked for the exclusive first viewing. Two of the characters lampshade the trope by discussing how the events of the episode are similar to an Agatha Christie novel, and to Big Brother. The murderer turns out to be the mother of the dead artist, and the artist did not plan or know about the murders; her motive is that she feels each of the characters, who were donated an organ by the artist, were ungrateful. The final twist is that the last character left alive manages to kill the mother and takes credit for the art exhibition.
- "Who Done It?" by Harry Nilsson. It starts out as a straightforward version of this trope, with 13 characters in a house who start dying, but eventually the narrator ends up alone and gets arrested and sentenced to death despite proclaiming his innocence. It's up to the listener to decide if this is outcome G or H, since two of the characters disappear from the song without explanation: the butler and his wife.
- Subverted in Zehn Kleine Jägermeister, a parody of the Ten Little Indian Boys rhyme by Die Toten Hosen, in which the titular Jägermeister die accidentally, generally because of their very poor judgment.
Role Playing Games
- The World Of Darkness series is somewhat notorious for setting up this trope ad nauseum. Any time a vampire hosts a party, you can guarantee he's going to be dead by the end of the night.
- The 1E Ravenloft module's sequel, House on Gryphon Hill, features Strahd von Zarovich as The Mole within the Weathermay household, and the entire population of Mordentshire as its Ten Little Murder Victims...with the added twist that not all the victims are being murdered: most are being possessed by Strahd's minions and turned into Moles as well.
- Note: don't try this in a system that allows for "raise dead", as Mr. Welch, DM found out once.
- The Butler Did It, another comedy parody of this genre. A woman invites her favorite mystery authors to her mansion, and one by one they begin getting murdered. Characters start throwing in red herrings simply for the sake of having red herrings, and in the end the wacky maid reveals she is actually the killer-and not actually that wacky.
- The Mousetrap, also by Christie, did this, in which the characters were guests at a hotel trapped due to a snow storm.
- There is also a stage adaptation of And Then There Were None, also penned by Christie.
- Something's Afoot is a broad musical parody with the characters dying in increasingly absurd ways ranging from a man-eating vase to a pygmy hidden in a potted plant. As usual, there is a man and a woman left as the last survivors. While celebrating their survival, they accidentally drink the poisoned wine.
- In the play But Why Bump Off Barnaby?, Barnaby claims that one of the guests isn't who he seems, and writes part of the person's name before dying. Most characters have those three letters in their name.
- The Elder Scrolls IV: Oblivion has fun with this trope. During the 'Whodunit?' quest, this sort of plot is set up where 6 people, including the Player Character, are all invited to a mansion, told it's a competition for treasure, and that they will be locked in until somebody finds it. Then people start dying. The amusing part? It's a mission for the Dark Brotherhood, AKA the Assassins guild; YOU are the murderer, hired by the mansion's owner to help him get revenge on the other 5 "guests". You actually get a bonus if you manage to kill them all without anybody discovering that YOU are the killer.
- For extra giggles you also have the key to the mansion.
- This is the premise of the amateur adventure video game 5 Days a Stranger (part one in the Chzo Mythos/John De Foe Quadrology series by Ben "Yahtzee" Croshaw): 5 people from different walks of life are lured into a house, one by one, and become trapped. Pretty soon they start dying. Each and every one of the five is a suspect, including the protagonist.
- It turns out the culprit is a ghost, and has been possessing multiple different people—including the protagonist.
- The other games in the series can be said to follow the same trope, especially the second (7 Days a Skeptic), set on a spaceship with no means of escape.
- That is actually the name of a map extension in Makai Kingdom
- The game Seven Noble Kinsmen has seven Shakespearean actors plus the player character, a theatre critic who ruined the actors' careers, invited to an isolated mansion/theatre by a mysterious host who never shows up. Then people start dying off...
- Interesting in that the murderer changes with each game play (the clues to his/her identity are also changed).
- This is the premise for a couple of roleplaying games using the Byond engine.
- The Point-and-Click computer game The 7th Guest uses this as a base premise—with a twist. A mad toymaker lures guests into a house he built and makes them solve riddles. If they solve all of them, they'll get whatever they most desire. Unfortunately, these wishes have an ironic twist—if the guest doesn't expire in the course of the game. Thing is, he only lured six people into the house. The seventh guest? A little boy who turns out to be you—and you were Dead All Along.
- This is the premise of the Laura Bow PC adventure game The Colonel's Bequest and its sequel The Dagger of Amon Ra. The first game takes place on an old plantation in 1920s New Orleans where the protagonist Laura Bow's friend has invited her to stay with her family, who have gathered to hear the old Colonel's will. When it's revealed that the Colonel's will is that his fortune be split equally among his loved ones who outlive him, people quickly start dying, and you are forced to collect clues to try and figure out who killed who, and why. The second game takes place in a museum following a robbery, and one by one everyone inside starts getting bumped off. In both games it is up to the player to figure out just what is going on, and if you get it wrong (or in the second game, don't have the evidence to prove that you're right) you will get the bad ending and let the murderer escape, perhaps at the cost of your own life.
- Text adventure game Delightful Wallpaper is a version of this, with the PC (apparently invisible to the NPCs) placing various "intentions" around a mansion which drive the guests to kill each other.
- Mega Man Battle Network 2 has a portion spent like this. A group of Official Netbattlers, including the hero, Lan, and the rival, Chaud, are gathered in a castle for a meeting. It eventually turns out that not only was there a spy in their midst, the spy is the innocent-seeming Princess Pride, who faked being attacked early on. You learn this after both Lan and Chaud have already been left the only two suspects, and have fought to the Disney Death out of paranoia.
- The Garry's Mod has couple of gamemodes with this kind of premise.
- In Calm Time, the main character invites some people to a party on his house in the countryside, a place far from civilization with not even cellphone coverage. It is possible that the protagonist chose this place to make it easier to trap people in there and murder them.
- Until Dawn subverts this. The first portion of the game has eight young friends gathering in a ski lodge to hang out, on invitation by one member of the group, where they soon find out that they're being stalked and menaced by a Slasher Movie-style serial killer who kills at least one of them. It then turns out that the one who is murdered, who was also the one who invited the rest, actually is the killer, and did invite his friends up as targets... of a particularly intense prank; he's not a killer at all. While the kids do turn out to be in real danger, its source isn't targeting them specifically, rather than taking advantage of their being there.
- In Nine Hours, Nine Persons, Nine Doors, the characters have been kidnapped by a mysterious person called Zero to play a "Nonary Game". But some of the players know each other in a less-than-friendly context, and they aren't all able to go through the final door. You do the math...depressingly, though, it turns out the game is designed so all players survive by the end if they cooperate. While they can't all go through the final door, there are two final doors that would allow everyone to get through. Also, the only people in any real danger are those who made the first Nonary Game, the one played during the game being the second.
- A large part of Umineko: When They Cry's plot is based on this trope, fittingly, considering that the whole story is a Whole Plot Reference of the Trope Namer. Between a Succession Crisis and a bizarre riddle counting off the visitors' horrific deaths (most of them in closed rooms) in a witch resurrection ceremony, the characters can't figure out whether they're being bumped off by each other or by an actual witch. And to add a meta-layer, you soon realize that the third-person narration is often outright lying (though the way it lies and what it shows often serves as a hint). Oh, and if the hero hasn't found the culprit when time runs out, the two days reset and another murder scenario starts. In the end, it turns out that not only is the culprit among the 18 people, they want to be discovered and stopped. All in all, this is quite a zig-zagging example.
- Dangan Ronpa has an interesting example: the presence of a mole is not revealed until the fifteen students have been whittled down to seven, and the mastermind immediately reveals the mole's identity in the hope that someone will murder him/her. There was also a second mole who was betrayed by the mastermind and murdered in the first chapter.
- Super Dangan Ronpa 2 goes a step further by having the mastermind reveal from the start that one of the sixteen students is a "traitor". However, this "traitor" is not a murderer but an observer sent to help the students. Furthermore, the knowledge of this "traitor"'s presence does not drive anyone to murder out of paranoia: the murderer of Chapter 5 claims to be doing it to flush out the traitor, but that turns out to be a bluff.
- In Jack, the titular grim reaper takes the souls of 5 people killed in an explosion, and leaves it to them to find out who planted the bomb. Given the way the story was resolved it seemed likely that Jack was doing it in order to give some of them (particularly an individual in the group who had already suffered loss as Jack took someone he loved in a previous arc) a chance at last minute redemption and closure that if he just took them as is more would have gone to hell than actually did. Character development by that point had him doing what he could to help souls escape damnation and since he had already had 'monitors' following him around decided to put them to a positive use with their ability to create temporary zones like was done in that story.
- Used in KateModern during the "Trouble in Paris" arc, in which the situation is complicated by several characters having their own secrets, and by the fact that, with one exception who ISN'T the mole, the characters are all friends and protagonists.
- Back when Neopets was intended for college students, there was the "Ski Lodge Murder Mystery", which consisted of (avatars of) staff members being stranded in a Ski Lodge in a snowstorm.
- The plot of Ten Little Roosters, where ten members of Rooster Teeth are locked in their studios for the night with one of them being the killer. Interestingly, a lot of the plot points used in connection with this trope are defied. The idiots (Gavin and Chris) are killed off early, The Hero doesn't exist (Miles attempts to be The Hero, but it doesn't pan out) and everyone would rather just go and hide somewhere and wait for the cleaning lady to come and unlock the door in the morning so they can all leave.
- Edgar Allan Poes Murder Mystery Dinner Party has this as its primary plot. Edgar Allan Poe invites fellow famous writers to his home, offering them with a fake murder mystery that soon turns all to real. The guests even include Agatha Christie, who runs suspiciously late and misses the first murder.
- Spider-Man and His Amazing Friends: In "Seven Little Superheroes," the Chameleon invites Spider-Man, Iceman, Firestar, Captain America, Doctor Strange, Namor the Sub-Mariner, and Shanna the She-Devil to an island where they are trapped by a forcefield and targeted one at a time. The episode's name even reflects the alternate name of the novel. Too bad Aunt May's puppy sneaks in and then becomes a Spanner in the Works, since she acts as an Evil-Detecting Dog...
- Looney Tunes and Merrie Melodies:
- "The Case of the Stuttering Pig", starring Porky Pig. On a dark and stormy night in a large, spooky mansion, Porky's rich uncle has announced his will through his attorney, Goodwill, that he, Petuna, and his four brothers (Patrick, Percy, Portis, Peter) will inherit the fortune...but if they're all dead when the uncle dies, Goodwill gets the money. After Porky, Petunia, and his siblings leave, Goodwill reveals to the audience his true self as a money-hungry fiend who intends to kill all six pigs and inherit the money; he drinks Hyde formula and transforms himself into a monster. Later on, Goodwill kidnaps Porky's brothers one by one and then Petunia as they're walking through the mansion. Eventually, Porky finds Petunia and his siblings tied up in stocks in Goodwill's laboratory, and the main protagonist frees them...only for the fiend to break in and eventually corner everyone and kill them. Before that happens, a chair suddenly is thrown out of nowhere and knocks Goodwill silly, allowing the pig sextet to get the upper hand and subdue the monster in the stocks where Goodwill had restrained them earlier. Just before the iris-out—and presumably just before the police arrive to take Goodwill into custody for fraud and conspiracy to commit murder—the pigs wonder where the sudden assist came from. An off-camera voice shouts out "ME!" When the shocked monster asks for an explanation, the voice replies, "I'm the guy in the third row, ya big sourpuss!!!" The ultimate hero, it turns out, was one that Goodwill (shortly after turning into his monster alter-ego and revealing his diabolical plan) had specifically tried to intimidate earlier.
- A Futurama episode, "Anthology of Interest I" features a story entitled "Dial L For Leela" that features this.
- The Scooby-Doo episode "A Night of Fright is No Delight" (the one with the Confederate money.)
- Two, count them, TWO Adventure Time episodes featured this trope: "Mystery Train" and "The Creeps". Both of them were practical jokes that all the apparently "killed" people were in on.
- An episode of Police Academy featured "Agatha Crusty" and "Ten Little Coppers".
- Hulk Hogan's Rock 'n' Wrestling featued an episode called "Ten Little Wrestlers".
- Transformers Animated has this in the Flash Back filled episode "Autoboot Camp". Wasp was framed, and the real mole went on to become the head of Autobot intelligence while Wasp slowly went insane. Way to go, Bumblebee.
- Family Guy took on this one in "And Then There Were Fewer". It was Diane Simmons in the dining room, the living room, the upstairs hallway, and an upstairs balcony with, respectively, the gun, the knife, and the Golden Globe.
- These are sometimes acted out in real life as a form of life-action entertainment / improv. People show up to a set and are given character names and act out in real time a murder mystery where one of them is the killer. Sometimes even the "killer" him/herself doesn't know the character they're playing is the killer. Needless to say they're a ton of fun.