One of the basic building blocks of plot, a Plot Twist is a sudden, unexpected change in the fortunes or situations of the characters, setting, or plot.

Plot Twists are usually based on the assumption that there is something going on that we, the readers/viewers/players, don't know about; if we had known about it, it would hardly be surprising. When it is revealed to us, we are surprised and shocked. This includes hidden aspects of particular characters' backstories or their personalities ("I never would have thought Alice could kick Bob's head into the locker!")

Sometimes even when we do have all the information, the twist can come as a shock due to a sudden, unforeseen action by other actors in the plot, the setting or place it's occurring in. We could see an action that we'd long predicted but not all its ramifications, so the shock value is still there. Alternatively, while we've seen characters' emotions, we may not always be clued into the extent of their thoughts, so a particular action may still come as a shock.

A good Plot Twist relies on the viewer not to figure it out in advance. An obvious twist isn't much of a twist at all. When the viewer already knows the twist, due to being previously spoiled, the twist might not be as satisfying, but the opposite can also be true — you appreciate all the work that went into setting up the twist more once you know it. Of course, you can always have it both ways by avoiding spoilers the first time, then re-watching or re-reading the work. On the other end, if a plot twist is too obscure, it can leave the viewer feeling cheated — how could anyone have guessed that?

Note that Plot Twists refer to twists in the overall plot, and generally have lasting effects. An individual scene, such as a fight scene, can have several reversals in the fates of the combatants, but none of them can be called a Plot Twist. If the twist is of minor significance to the overall plot, it does not fall into this category.

Contrast Dramatic Irony, which is where the audience knows something that one or more characters do not. A common form of Shocking Moment.

Tropes:

• Accidental Public Confession
• Actually a Doombot: The villain the hero was fighting turns out to be a robot double or clone of the real villain.
• All Just a Prank: A major plot ends up to be a practical joke.
• Ass Pull: An explanation or solution that comes out of nowhere and disregards what has already been established by the story, named from the idea that the writer just pulled an answer from their ass in desperation for a quick and convenient way to resolve the conflict.
• Backstab Backfire
• Be Careful What You Wish For: A character makes a wish. Once the wish is granted, they learn the hard way that there are downsides to what they wanted.
• The Big Bad Shuffle
• Booked Full of Mooks: A character in a public space discovers that all the bystanders around them are actually another character's employees or co-conspirators.
• The Cake Is a Lie
• Canon Character All Along: The adaptation features a character who initially appears to be a completely new character created for the adaptation, but it later turns out that the character is really the adaptation's interpretation of an already established character.
• Career-Ending Injury
• Captain Obvious Reveal: A twist that is too easy to figure out before it's revealed.
• Chair Reveal
• Confirm Before Reveal: A character asks a quick question about something they're about to reveal before revealing it.
• Cosmic Horror Reveal: A work that starts out as a different genre before being revealed to be a Cosmic Horror Story midway through.
• Daydream Surprise: A brief scene is immediately shown to only be a daydream one of the characters is having.
• Decoy Protagonist: For when it turns out someone else was the main character.
• Deus ex Machina: Something comes out of nowhere and solves the conflict.
• Diabolus ex Machina: Something comes out of nowhere to create a new conflict
• Didn't See That Coming
• Died in Ignorance: A death occurs before an important revelation that may completely change the context of a scene.
• The Dog Bites Back: Someone gets back at those tormenting them.
• Doom as Test Prize
• Earth All Along: What was thought to be an alien planet turns out to really be Earth.
• Easily-Overheard Conversation
• Edible Treasure
• Everyone Is a Tomato
• Family Relationship Switcheroo
• Fake Mystery: The crime turns out to be staged/faked.
• Fake-Out Twist: A twist that is immediately twisted by another twist.
• First-Episode Twist: Tends to be a central part of the premise, even if it was hidden from the audience at first.
• Fantasy All Along: It turns out the events were all just part of someone's delusion.
• Formula with a Twist
• Game Changer
• Genuine Imposter
• Halfway Plot Switch
• Hidden Purpose Test
• Hijacked by Ganon: An entry in a series with a new villian has an iconic pre-established villian take over as the main antagonist.
• Human Alien Discovery
• Hybrid All Along
• I Am Not Your Father: A father reveals to his child that they were adopted.
• I Am Who?
• I Made Copies: A character tears up a contract only to be told copies were made.
• Insanity Establishment Scene: When a character is revealed to be crazy later instead of from the start.
• Internal Reveal: The Reveal in-universe.
• It Was with You All Along
• Left for Dead
• Luke, I Am Your Father
• The Man Behind the Curtain: An influential and previously unseen Big Bad is revealed to be pathetically weak.
• Memory-Restoring Melody: A crucial plot point is revealed when a character who previously forgot or suppressed it listens to a certain song.
• Mid-Season Twist
• Monster Suit
• Nested Story Reveal
• Never the Obvious Suspect
• Nice Job Breaking It, Hero: The hero tries to save the day, but their efforts end up making things worse.
• Non Human Lover Reveal
• Nothing Is the Same Anymore
• Not Quite Dead: Someone thought to be dead turns out to be still alive.
• Not So Episodic: Early episodes turn out to be connected.
• Not So Remote: A person thinks they're far from civilization, but ends up discovering they're closer to home than they thought.
• Not Too Dead to Save the Day
• Ominous Adversarial Amusement
• The Picture Came with the Frame
• Photo Doodle Recognition: Recognizing someone by drawing their disguise or distinguishing features on a photograph where they don't have them.
• Poorly Timed Confession
• Post-Mortem Comeback
• Prophecy Twist
• Prophetic Fallacy
• Propping Up Their Patsy: A culprit proclaims the innocence of another suspect to conceal their own culpability or further their own agenda.
• Proscenium Reveal
• Really Royalty Reveal: Someone who believed themselves to be a peasant or commoner discovers they're actually royalty.
• Redeeming Replacement: A villain gets a heroic successor who aims to do good in order to make up for their predecessor's crimes.
• Released to Elsewhere: People are executed and the authorities lie that they were simply relocated to new places.
• Resemblance Reveal
• The Reveal: The story reveals something to the audience that wasn't known before.
• The Reveal Prompts Romance
• Reverse Relationship Reveal
• Robotic Reveal: A supposedly organic being turns out to really be a robot.
• Role-Reversal Boss: In a game, the player unexpectedly finds themselves controlling a boss character.
• "Save the World" Climax
• Secretly Dying
• Secret Test
• Secret Test of Character
• Stalker Shot
• "Stop the Hero" Twist
• Storm in a Teacup: Failing to get a task done in time. It turns out, it wasn't necessary.
• Stranger Behind the Mask
• The Story That Never Was
• Superweapon Surprise
• Surprisingly Mundane Reason: The characters believe that another characters actions are for some outlandish/profound reason, only for it to be revealed that they were actually doing as they did for mundane reason.
• Survival Through Self-Sacrifice: A character chooses to sacrifice his or her life, and is spared for doing so.
• Take a Third Option: When someone has to decide between two choices, they work around and pick a third choice.
• Tomato in the Mirror: A character discovers that they are not what they think they are.
• Tomato Surprise: Something is known to the characters in-universe, but is revealed to the audience as a twist.
• Two Aliases, One Character
• Twisting the Prophecy: Knowingly fulfilling a prophecy in a way that creates a favourable outcome.
• Undercover Cop Reveal: A person turns out to be an undercover cop.
• The Unreveal: Even when it looks like the big secret will be revealed, it never is.
• The Un-Twist: Deliberately setting up a Captain Obvious Reveal while also hinting at a Red Herring, so that the audience is surprised when it's played straight.
• "The Villain Knows" Moment
  • Villain Reveals the Secret
• Unexpected Character: The work features a character in the franchise that audiences did not anticipate to be involved.
• Unreliable Narrator: It is hinted that the narrator may be exaggerating or glossing over parts of the story, if they weren't just outright lying.
• Villainous Legacy: The villain continues to inspire bad deeds long after they have died.
• Waking Up Elsewhere
• Wham Episode: An episode that suddenly changes the series' tone from then on.
• Wham Line: The mood of the work changes abruptly all because of a single line of dialogue.
• Wham Shot: A single scene changes everything.
• Won't Do Your Dirty Work: The hero/villain is told to solve his own problems.
• Worthless Treasure Twist
• Yank the Dog's Chain: Right when it looks like this unfortunate person will finally have better luck, their chances at happiness are ruined at the last minute.