Memento is a 2000 psychological thriller film written and directed by Christopher Nolan, adapted from his brother Jonathan's short story "Momento Mori". It stars Guy Pearce as Leonard Shelby, a former insurance fraud investigator searching for the man he believes raped and killed his wife during a burglary. Leonard suffers from anterograde amnesia, which he contracted from severe head trauma during the attack on his wife. This renders his brain unable to store new memories. To cope with his condition, he maintains a system of notes, photographs, and tattoos to record information about himself and others, including his wife's killer. He is aided in his investigation by Teddy (Joe Pantoliano) and Natalie (Carrie-Anne Moss), neither of whom he can trust.

This feature is often used to show the distinction between plot and story. The film's events unfold in two separate, alternating narratives—one in color, and the other in black and white. The black and white sections are told in chronological order, showing Leonard conversing with an anonymous phone caller in a motel room. Leonard's investigation is depicted in five-minute color sequences that are in reverse chronological order. As each scene begins, Leonard has just lost his recent memories, leaving him unaware of where he is or what he was doing. The scene ends just after its events fade from his memory. By reversing the order, the spectator is unaware of the preceding events, just like Leonard. By the film's end, the two narratives converge in a single sequence that begins as black and white and fades into color.