An episode in which a main character and the audience are kept in the dark by the character's friends or colleagues. This is to pull off a sting against someone else, never a main character.
They will be given the excuse at the end... "We would have told you, but we needed your reactions to look genuine." In settings that include telepathy it's often done to foil even that.
A character who just loves to keep others intrigued may sometimes use this as a pretext.
It's a Not Himself with the numbers inverted.
When this is done to the actors, it is Enforced Method Acting.
- Lelouch does this to himself - he erases his own memory of making a plan and telling Suzaku how to follow it, so that Mao won't be able figure it out by reading Lelouch's mind in an episode in the middle of season 1.
- In the second season he does it to the whole world so that his Zero Requiem would work out.
- The Locked Room Mystery in Haruhi Suzumiya was all set up by the organization. Koizumi could have told at least Kyon what was going on, but... In the novels, it's not Haruhi who figures it out but Kyon, who then tells Koizumi that he's not as stupid as he acts.
- In Fruits Basket, the fact that Akito is a woman is kept a secret not just from Tohru, but from all the cursed Sohma save for the ones already present at the time she was born (Shigure, Ayame, Kureno and Hatori). When Kureno tells this to Tohru, she has an Heroic B.S.O.D..
- Edward Elric is on the receiving end of this trope (along with his brother and Major Armstrong) in Fullmetal Alchemist. Mustang and his team do a lot of investigating offscreen and determine that they need to get Maria Ross out of prison before she's murdered by the people who framed her for Hughes' death. Consequently, Mustang pretends to burn Ross alive, while actually helping her escape and then purposely allows Ed and everyone else to believe his actions were genuine, enraging them in the process. He even punches Ed in the face and casually dismisses Armstrong's grief to keep everyone suitably riled enough to be convincing. He then sends both Ed and Armstrong off on a mission that culminates in them happily meeting a very much alive Ross.
- Sailor Moon. In the Sailor Stars anime, Kakyuu was actually hiding in a small teapot that Usagi's "adoptive sister" Chibi-Chibi had all the time with her. After she finally appears to save Usagi's life, she apologizes to the Sailor Starlights and tells them that she was healing her injuries inside the teapot and wasn't able to just appear in front of them until it was time.
- In JoJo's Bizarre Adventure: Stardust Crusaders, when Polnareff discovers that Avdol survived the battle with Hol Horse he rushes to tell the rest of the group...and they say that they already knew, but they didn't tell him because they knew he'd blab it and they wanted Avdol to be able to rest and recover without one of DIO's assassins coming after him.
- In one Black Canary miniseries, when Black Canary's adopted daughter Sin is kidnapped, Green Arrow makes it appear that the rescue attempt, badly bungled, killed Sin. He knows the kidnappers will watch Black Canary and note if she does not show grief, so he keeps her in the dark to make sure her reaction will be authentic, and he does not expect her to forgive him when he reveals the truth.
- The Flash. In one issue of Impulse, Max and The Trickster pull off a plot like this to take down a pair of mob bosses.
- Iron Man. The reason Tony Stark didn't tell Jim Rhodes about faking his death so he could undergo experimental reconstructive surgery was exactly because Stark wanted Rhodey's reactions to his "death" to be genuine, so Stark's opponents wouldn't come looking for him. Once Stark came back, Rhodey was pissed, and the incident left their friendship broken for a long time.
- Judge Dredd: In the "Trifecta" arc (a Crossover with Low Life and The Simping Detective), Judge Dredd is revealed to have been instrumental in setting up a counter-plot against the imminent coup d'etat attempt by the head of Black Ops against Chief Judge Hershey. Hershey herself and even one of Dredd's collaborators (through Laser-Guided Amnesia) were kept in the dark about this until the finale.
- In the movie Chicago, Billy Flynn doesn't tell Roxie that he made it seem like the prosecutor had tampered with her diary in order to keep her from screwing up his plan during her trial.
- In The Dark Knight, Gordon fakes his death, ostensibly for his family's safety, but the reveal happens so quickly and in the middle of the film's biggest escalation scene that you might miss his reasoning on the first viewing. Or the seventeenth.
- Independence Day. The Secretary of Defense decided not to tell the President of the U.S. about Area 51 (where the alien spaceship was being studied) because of "plausible deniability". It was established in his dealings with his family that the President was a bad liar, and if he had known about Area 51 he wouldn't have been able to effectively lie if questioned about it (e.g. by a reporter).
- Older Than Television: Sherlock Holmes does this almost constantly, to almost every single character. A fundamental part of his Insufferable Genius character.
- "The Adventure of the Dying Detective" (1913)
- After faking the symptoms of an exotic disease, Holmes provides the page quote while speaking to Watson. As Holmes further explains, while he didn't have a great deal of confidence in Watson's ability to deceive, he did have a great deal of confidence in Watson's abilities as a doctor, which is why he was so insistent that Watson not touch him—a cursory examination by Watson would have revealed the ruse immediately.
- In Bert Coules's radio adaptation, Watson fails to accept Holmes's No Hard Feelings at the end, instead calling him out not only for the deception, but for asking Watson to hide in the room as a witness, and then forgetting about him.
- "The Adventure of the Empty House". An even more extreme example occurs after his final brush with Moriarty, after which he pretended to be dead for three years. Revealing the truth that time nearly gave Watson heart failure.
- "The Adventure of the Dying Detective" (1913)
- Hercule Poirot pulled this one all the time (except that he rarely gives a reason). The pinnacle is The Big Four, where he explains to Hastings after the event that his plan to take the Four down required "your own knowledge and belief that there was such a person as Achille Poirot!"
- Occurs in The Light Bearer (a historical fiction novel about ancient Rome). The male protagonist allows his aunt Arria to think her children have died in a fire in order to save them from abduction by Nero. Since Nero was in the room when the announcement was made, the protagonist knew he would not have been fooled if Arria had not expressed real shock and grief.
- The entire plot of Mordant's Need (the first novel of which is The Mirror of Her Dreams) by Stephen R. Donaldson revolved around a king pretending to be insane to drive away his allies. He needed to appear weak.
- Lucky Starr pulls this all the time, often dramatically accusing the wrong suspect on purpose and using people's reactions to gain proof against the real culprit. The worst instance is in Lucky Starr and the Rings of Saturn, in which Lucky allows everyone to believe he is going to betray Earth—including his best friend, who thinks Lucky is turning traitor in exchange for the friend's life.
- In the last few pages of The Hunger Games: Catching Fire, it turns out that Katniss' friends kept her in the dark about some pretty huge things, including the fact that District 13 really exists, because Katniss' poor deception skills and Chronic Hero Syndrome would have ruined their plans if she had known. Also, in case the Capitol captured Katniss or Peeta ( and they did capture the latter), they wouldn't know anything about the plans.
- In the Diogenes Club short story "Sorcerer, Conjurer, Wizard, Witch", the late Mycroft Holmes's Batman Gambit to take down Colonel Zenf relies on Zenf believing that one of the four guardians of London's magic is a traitor ("a Rat amongst the Ravens"). For this to be convincing, Mycroft's successors at the Diogenes must also believe one of the Ravens is a Rat, and evidence to this effect is provided to them, in part by the Ravens themselves.
- Done in When True Night Falls, where Tarrant's plan to gain an opportunity to try to kill the Undying Prince required Vryce's ignorance. His apology for the ruse at the end is sincere.
- In an episode of Babylon 5, Londo leads Vir to believe he is planning to kill G'Kar, when in actual fact it was part of a greater scheme to make rival Lord Refa (who has a telepath on his payroll) think that was the plan and go after G'Kar first, so that G'Kar could kill Refa for Londo. Vir, of course, isn't happy about being used in this manner, and is further angered when Londo states that Refa would believe him too unimportant to kill (as it implies that Londo also thinks that, even if the truth is quite different).
- The Buffy the Vampire Slayer episode "Enemies" uses this as well; Angel fakes turning evil to trick Faith, and really punches Xander (who was clueless) in the face during the masquerade. Whether the pleasure he took in doing so was real is left ambiguous.
- Cheers did this a lot, such as the episode in which Coach and Harry the Hat conspired to recover Coach's money from a con by Harry pretending to betray the coach. Diane whined that they would have helped, but Harry replied, "Coach and I didn't think you weren't smart enough to pull it off."
- The first episode of Hustle with Danny (and the audience) only let in at the end.
- Happens a great deal in Hustle actually, due to a combination of the Unspoken Plan Guarantee, in-character Enforced Method Acting (as in the first episode, where the realism of Danny's reactions to the unfolding situation were vital. It was also a trick to test his loyalty, as in the next point) and, in some cases, the characters tricking each other (as in the Season 3 episode where Mickey and Danny get dumped naked in Trafalgar Square for a contest to determine the leadership of the crew).
- Stargate SG-1 uses this at least three times:
- "Crossroads": SG-1 is kept in the dark by the Tok'ra.
- "Shades of Grey": Everyone is kept in the dark by Hammond, O'Neill and a couple of alien races.
- "Dominion": Vala is kept in the dark about her own plan (thanks to a memory-altering device) to fool her mind-reading Big Bad daughter Adria.
- Stargate Atlantis: O'Neill does it again in order to fool the Asuran Replicators, whom he knows have the ability to Mind Probe people. He and the team give a bogus plan to Woolsey, knowing the Asurans will get it out of him, while they enact their real plan behind everyone's backs.
- Star Trek: Voyager did this with Tom Paris - during the second season he became a much more shady and Jerkass character (gambling, mouthing off at Chakotay, showing up late for duty, etc.) until he finally asked to be put off the ship. It turned out that it was a ruse cooked up by Janeway and Tuvok to try and find the crewman feeding information to Seska, and Chakotay was kept in the dark in case the spy was one of his former crewmen. Needless to say, Chakotay was very unhappy when he found out he'd been played yet again.note
- The radio drama of Return of the Jedi contains one of these, though it wasn't explained in the film. C-3PO was deliberately kept in the dark about Luke's complicated plan to rescue Han Solo from Jabba the Hutt, so that when Jabba had Threepio's data files scanned and found no trace of the stratagem, he accepted the droid's story at face-value. (R2-D2, meanwhile, was in on the whole thing.) Leia later apologizes to Threepio for the deception.
- Done by The Illusive Man quite often in Mass Effect 2.
- Also done by the Shala'Raan during Tali's trial by not informing Tali that her father is dead so that the court could see her shock.
- In Star Wars Knights of the Old Republic, Bastila would have been ready to tell the player character that s/he is Revan but the Jedi Council forbid her, for they feared that evil would be let loose on the universe again. Depending on the player character's reaction, this may bring on the very nightmare their actions were intended to prevent.
- In Persona 3, Mitsuru knows more about Tartarus and the Dark Hour than she initially lets on.
- Persona 5: When Sae asks why the Phantom Thieves didn't upfront tell her that Goro was working for a conspiracy that was using the Palace to commit crimes, the Thieves reply that 1) Sae wouldn't have believed them and 2) they needed Sae in the dark for their plan.
- The Men in Black cartoon. J is kept out of the loop on Zed's phony retirement, so that the alien frankenstein Alpha will read J's mind and believe the lie. Unfortunately for the MIB, J had his doubts, and Alpha saw through the deception.
- In Scooby-Doo! in Where's My Mummy?, Velma and Prince Omar don't tell the rest of the gang about their plan to scare off the treasure hunter Amelia von Butch with a Cleopatra ghost—as Velma later explains to her friends, she ultimately did it to try and protect her friends, feeling that what she and Omar had in mind was too dangerous for them.
- An episode of Transformers: Beast Wars had Rattrap switch sides, which was set up by Optimus and himself so they could find out how the Predacons were tapping their transmissions.
- In Teen Titans, Robin did this in the episode "Masks".
- Raimundo pulls this off against Hannibal Roy Bean in one episode of Xiaolin Showdown by pretending to join him.
- In the '90s Iron Man cartoon, Tony does this twice. The first time, a fake marriage to Julia, is played for laughs. (Apparently it was important that Wanda's jealousy be realistic.) The second time, in which Tony fakes his death, does NOT amuse the team — they kick him out and relocate. The second season also treats the fake-marriage stunt a bit more seriously.
- Where on Earth Is Carmen Sandiego?: Zack and Ivy actually try to tell their AI Chief about something they're doing, but then Carmen brags about how she's hacked the Chief, and they realize they can't tell him that Ivy is pretending to be "The Tigress", a rival thief to Carmen, as part of a plan to catch her once and for all...a plan that almost works.