The film was originally written with famed comic actor Bob Hope in mind, but after Universal purchased the script, they retooled it to star their own high-earning comedy actors. For a time in preproduction, it was titled Abbott and Costello Meet the Killers, but it was renamed after Boris Karloff was hired five days before shooting.
House detective Casey Edwards (Abbott) and hapless bellboy Freddie Philips (Costello) work at the Lost Caverns Resort Hotel. When famed criminal attorney Amos Strickland checks in, he gets in a fight with Freddie, and gets him fired. Freddie finds his murdered body, and he certainly looks guilty of killing Strickland himself he took Stricklands bloodied handkerchief without thinking about it, and the gun used to kill him was found in his bedroom. Though Casey tries to clear his name, even going so far as to plant the gun elsewhere, police inspector Wellman and Sgt. Stone keep Freddie in his hotel room while they investigate. However, there are 8 more suspects in the case at the hotel: Stricklands secretary Gregory Milford, and 7 of Stricklands former clients, including the sinister Swami Talpur (Karloff). Apparently, Strickland was about to publish his memoirs, and said clients are more than a little hesitant for their criminal pasts to come out into the open. All of them are willing to let Freddie take the fall for the murder, especially since Angela tricked Freddie into writing and signing a confession note that the former cons now have but the only way they can make sure Freddie doesnt refute the note is if hes dead.
The film is generally seen as a fairly well-made, solid movie, leaning more towards a straight parody of Film Noir than Abbott and Costellos usual silliness with murder mysteries and horror movies, and today its often looked on as something of an underrated gem.
Fun fact: the film still holds the Hollywood record for having the most actors names in the title of a single movie.
This film provides examples of:
- Abhorrent Admirer: Abernathy, a hotel employee, comes on to Freddie quite persistently while he's Disguised in Drag.
- After-Action Villain Analysis: At the very end, Inspector Wellman summarizes the entire case to the room with all the suspects and victims, and explains who the killer is. (It's not The Summation because the audience already knows Strickland was shot, they just don't know who did it, or why.)
- Affectionate Parody: Of Mystery Fiction and Film Noir clichés.
- Animated Credits Opening: A short one, with animated versions of Bud and Lou painting their names onto a big tarp on the side of a building, only to be scared by someone offscreen shooting at them.
- Better Manhandle the Murder Weapon: When Freddie unexpectedly finds a gun in his bed, he picks it up without thinking about it, then panics, bundles it into his sheets, and tries to leave the room.
- Blackmail: It seems hotel manager Melton and Stricklands secretary Milford were blackmailing Mr. Crandall, the hotels owner and a former client of Strickland. When Strickland found out, he came to the hotel to investigate, so Melton killed him with a gun stolen from Mike Relia, another of Stricklands former clients. What Crandall was being blackmailed over is never explained.
- Bottomless Pits: A huge, bubbling sulfur pit in the Lost Caverns is labeled as such, and Freddie nearly falls into it when hes threatened at one point.
- Bungled Suicide: Freddie has a whole string of these while being hypnotized by the swami. First, the swami orders him to put a noose around his neck and jump off the bed, but he pulls the ceiling fan down instead. The swami then tells Freddie to put his gun to his head and use it, but the "gun" turns out to be a spray bottle. He then orders Freddie to climb onto a windowsill and jump, and he does - right back into the room. Finally, he gives him a knife and tells him to to "plunge it into the heart of the man in the mirror". From Freddie's point of view, the swami is "the man in the mirror". Hilarity Ensues.
- Cat Scare: Freddie, jumpy at all the attempts on his life, gets badly startled twice in a row during a sunny day outside: first when a flowerpot from a ledge above gets knocked over by a cat and almost hits him, then when an arrow nearly misses him but its a suction-dart arrow shot by a kid.
- Chekhov's Gag: An increasingly nervous Freddie booby-traps his room in several places, and two of them catch Casey and Wellman as one-off gags but a third catches Melton in the climax when he tries to flee.
- The Comically Serious: Talpur becomes this while trying to hypnotize Freddie into killing himself, culminating in the immortal line "Youll commit suicide if it's the last thing you ever do!"
- Creepy Cave: The Lost Caverns Resort Hotel was built near the Lost Cavern nearby, which seems to be a big tourist attraction. However, when the heroes go in after-hours, they find it a dark, spooky, forbidding place.
- Digging Yourself Deeper: While Freddie is under suspicion, he seems to implicate himself further nearly every time he opens his mouth, like agreeing with Casey that a bellboy would have been able to enter Stricklands room easily.
- Disguised in Drag: Freddie dresses as a hotel maid while hiding Relia and Milfords bodies, so nobody can connect him with the murders.
- Dynamite Candle: The killer slips Freddie one while he's lost in the caverns near the end. When it explodes, it drives a grizzly bear out of hibernation.
- Exact Words: Abernathy asks Freddie for "a little smack" (kiss). A few seconds later, we hear a loud noise from the next room.
- Extendo Boxing Glove: Freddie's last booby-trap, set up in his closet. It clobbers Inspector Wellman at the very end.
- Femme Fatale: Angela Gordon, she seduces Freddie into signing a confession, then apparently poisons Freddies champagne and tries to seduce him into drinking it, but shes stopped by the police. It turns out the drink wasnt poisoned, though.
- Fiery Cover Up: Upon realizing he has a bloodstained handkerchief from the murder victim, Freddie panics and burns it offscreen. This just gets him in more trouble, since the detectives find the ashes, have them analyzed, and discover theyre from a bloody handkerchief found in Freddies bedroom.
- Frame-Up: And how. Not only did the original killer try to implicate Freddie by putting the murder weapon in his bed, but it turns out several people at the hotel have criminal pasts theyd rather not come to light in the investigation, and they all conspire to make Freddie look guilty and/or kill him themselves.
- He Knows Too Much: Relia is murdered because he found out that the killer "borrowed" his pistol to kill Strickland.
- "Home Alone" Antics: Freddie sets up several booby traps in his hotel suite to prevent the killer from either killing him or planting more dead bodies there. Casey and Inspector Welman fall victim to two of them, but a third ends up catching the killer.
- How Would You Like to Die?: The Swami is trying to hypnotize Freddie into committing suicide with various methods, but Freddie is Too Dumb to Fool and keeps resisting him. The Swami then offers Freddie the chance to choose his own means of death. Freddie's response: "Old age!"
- Hypno Fool: When Freddie runs into Swami Talpur at Stricklands door, Talpur quickly hypnotizes him into forgetting he was there before fleeing.
- Insane Troll Logic: When Freddie hysterically announces that Strickland has been murdered, Melton says, "That's impossible, we don't allow murderers in this hotel!"
- Instantly Proven Wrong: After Freddie booby-traps his doors, he mentions he didn't bother with the windows because a killer wouldn't bother with those - they're three stories up. Cue someone shooting at him through the window.
- It Was Here, I Swear!: At one point, Freddie finds Milford's body in his bed, and runs to get Casey. When he comes back, of course, Milford is gone. A few seconds later, it happens again in the bathtub... and again in a chair. He finally turns up in the bed AGAIN, where Casey finds him.
- Jump Scare: When Freddie comes up to Strickland's room to apologize for making a bad first impression, we get a Smash Cut to Stickland's corpse, accompanied by a Scare Chord. This is just for the audience, it takes Freddie several minutes to realize that Strickland is dead.
- Lightmare Fuel: All the murders and attempted homicides are objectively frightening, but more than balanced out by the madcap reactions from Bud and Lou.
- Mood Dissonance: When someone tries shooting at Freddie through the window, Casey is overjoyed... because they now have solid evidence that Freddie is innocent. Freddie's too freaked out and scared to care.
- Never One Murder: The killer keeps leaving more bodies around the hotel.
- Never Trust a Title: The killer is not Boris Karloff's character.
- Of Corpse He's Alive: While trying to hide Milford and Relias bodies, Freddie and Casey pretend to play cards with the corpses when hotel employee Abernathy shows up.
- Oh, No... Not Again!: After finding the body of Mr. Relia in his closet and hauling it off to hide, Freddie comes across the body of Mr. Milford in Caseys closet and also finds Relias body back in the laundry cart he used to haul it off.
- Ominous Owl: One spooks Freddie (and later, Casey) inside the Lost Caverns.
- Open Mouth, Insert Foot: Freddie accidentally admits that he hid Relia and Milford's bodies in an elevator, essentially confessing to the murders he's been wrongfully suspected of.
- Psychic-Assisted Suicide: Played for Laughs and averted. Swami Talpur tries hypnotizing Freddie into offing himself but Freddie has no intention of following through, and simply interprets his directions in such a way that dont hurt him, as Talpur grows more and more frustrated at his Too Dumb to Fool victim.
- Red Herring: Throughout the movie, the viewer is led to believe that the Swami is the killer. He isn't. For example, when the killer addresses Freddie through the air duct, it is very clearly the Swami's voice, not Melton's.
- Rewatch Bonus: Mr. Melton goes out of his way to accuse Freddie of the murders and even tells the cops that they're wasting their time with an investigation. That's because he's the killer.
- Sliding Scale of Comedy and Horror: Right about in the center, with several horrifying murders, a mysterious killer, and loads of wacky hijinks and wisecracks from Bud and Lou.
- Sauna of Death: Someone tries killing Freddie by turning the heat all the way up when he's locked in a steam bath. After the detectives rescue him, he downs an entire gallon of water in one gulp.
- Spoiler Title: The suspense of the plot is who the mysterious killer might turn out to be. Could it perhaps be the evil Swami, played by Boris Karloff? Watch to the end to find out... that the killer is not Boris Karloff's character at all! Not even close. It's Mr. Melton, the hotel manager.
- Twist Ending: Despite every indication given by the film (even the title!) the killer turns out to be not Boris Karloff.
- White Mask of Doom: The killer wears one in the Lost Caverns while stalking Freddie.