A memory inside a memory, Memento is a complicated head spinning adventure. Leonard is determined to avenge his wife's murder. However, unable to remember anything that happens day-to-day due to a condition he sustained, short term memory loss, he has to write himself note after note that still don't mean anything after he falls asleep. The film goes back in time to reveal each little bit of the puzzle as he tries to find out the person who killed his wife and makes the audience feel just as confused as he is. The narrative closely follows a phone call Pearce has in which he talks about Sammy Jankis a former client of his who he believed had the same condition. The film takes an unexpected twist as the two characters have a lot more in common than is initially put across.
Leonard is an insurance investigator whose memory has been damaged following a head injury he sustained after intervening on his wife's murder. His quality of life has been severely hampered after this event, and he can now only live a comprehendable life by tattooing notes on himself and taking pictures of things with a Polaroid camera. The movie is told in forward flashes of events that are to come that compensate for his unreliable memory, during which he has liaisons with various complex characters. Leonard badly wants revenge for his wife's murder, but, as numerous characters explain, there may be little point if he won't remember it in order to provide closure for him. The movie veers between these future occurrences and a telephone conversation Leonard is having in his motel room in which he compares his current state to that of a client whose claim he once dealt with.
Point blank in the head a man shoots another. In flashbacks, each one earlier in time than what we've just seen, the two men's pasts unfold. Leonard, as a result of a blow to the head during an assault on his wife, has no short-term memory. He's looking for his wife's killer, compensating for his disability by taking Polaroids, annotating them and tattooing important facts on his body. We meet the loquacious Teddy and the seductive Natalie (a barmaid who promises to help) and we glimpse Leonard's wife through memories from before the assault. Leonard also talks about Sammy Jankis, a man he knew with a similar condition. Has Leonard found the killer? Who's manipulating whom?