Abe Lucas (Joaquin Phoenix) is a college professor in a small New England town who is going through an existential crisis. He strikes up a relationship with a student, Jill Pollard (Emma Stone), which helps but doesn't alleviate him. One day, he overhears a woman talking about a custody battle she is in which is being screwed over by the presiding judge, and Abe has the perfect plan: kill the judge.
Tropes in this film include:
- All Girls Want Bad Boys: Rita says she would run away with Abe even if he turned out to be the murderer (this is all hypothetical though; she never finds out he did it as far as we can see). Averted with Jill, who's quick to break up with him after finding out.
- Chekhov's Gun: Abe wins Jill a flashlight at a carnival. It ends up saving Jill when Abe trips on it and falls into an elevator shaft.
- Deadly Deferred Conversation: Subverted. Jill reconciles with her boyfriend Roy and promises to explain everything on Monday. Abe makes his move to kill her beforehand, but Jill ends up surviving.
- Elevator Failure: How Abe plans to kill Jill: by tossing her into an empty elevator shaft. He ends up falling instead.
- Hoist by His Own Petard: Abe, who falls into the open elevator shaft he had rigged for Jill.
- I Never Said It Was Poison: The first hint to Jill that Abe was involved is that he mentions the poison as being cyanide. However, he is able to cover this by saying he assumes it is cyanide.
- It Gets Easier: Jill warns Abe that one murder opens the door to more murders after she finds out he killed the judge. She's proved right as Abe attempts to kill her to avoid being caught.
- Make It Look Like an Accident: The judge is initially reported to have died of a heart attack. Abe also rigs the elevator so that Jill would fall into the shaft, noting that he can make it look like a mechanical failure rather than rigged.
- The Needs of the Many: This is Abe's motive for murdering the judge, saying the world will be a better place if he's not in it.
- She Knows Too Much: Jill finds out everything about Abe's plan, leading him to attempt to kill her.
- Shout-Out: The whole plot is one to Crime and Punishment, which is explicitly reference in the film and noted for its parallels, while specifically the killer's rationalizations are similar.
- Teacher/Student Romance: Philosophy professor Abe and his student Jill have an affair.