The film starts with the Polaroid photograph of a dead man. As the sequence plays backwards the photo reverts to its undeveloped state, entering the camera before the man is shot in the head.A series of black and white sequences begin with Leonard Shelby, an insurance investigator, in a motel room speaking to an unseen and unknown caller. Leonard has anterograde amnesia and is unable to store recent memories, the result of an attack by two men. Leonard explains that he killed the attacker who raped and strangled his wife, but a second clubbed him and escaped. The police did not accept that there was a second attacker, but Leonard believes the attacker's name is John or James, with a last name starting with G. Leonard conducts his own investigation using a system of notes, Polaroids, and tattoos. From his occupation, Leonard recalls a fellow anterograde amnesiac: Sammy Jankis. Sammy's diabetic wife, who wasn't sure if his condition was genuine, repeatedly requested insulin for him to stop. As a result, she overdosed, subsequently falling into a fatal coma.Afterwards, color sequences are shown reverse-chronologically. In the story's chronology, Leonard self-directively gets a tattoo of John G's license plate. Finding a note in his clothes, he meets Natalie, a bartender who resents Leonard as he wears the clothes and drives the car of her boyfriend, Jimmy Grantz. After understanding his condition, she uses it to get Leonard to drive a man named Dodd out of town and offers to run the license plate as a favor. Meanwhile, Leonard meets with a contact, Teddy, who helps with Dodd, but warns about Natalie. However, a photograph instigates Leonard not to trust him. Natalie provides Leonard the driver's license for a John Edward Gammell, Teddy's full name. Confirming Leonard's information on "John G" and his warnings, Leonard drives Teddy to an abandoned building, leading to the opening.In the final black-and-white sequence, prompted by the caller, Leonard meets with Teddy, an undercover officer, who has found Leonard's "John G," Jimmy, and directs Leonard to the abandoned building. When Jimmy arrives, Leonard strangles him and takes a photo of the body. As it develops, the black-and-white transitions to the final color sequences. Leonard swaps clothes with Jimmy, hearing him whisper "Sammy." As Leonard has only told Sammy's story to those met, he doubts Jimmy's role. Teddy arrives and asserts that Jimmy was John G, but when Leonard is undeterred, Teddy reveals that he helped him kill the real attacker a year ago, and he has been using Leonard ever since. Teddy points out that since "John G" is common, he will cyclically forget and begin again and that even Teddy himself has a "John G" name. Further, Teddy claims that Sammy's story is Leonard's himself, repressing the memory to escape guilt.After hearing Teddy's exposition, Leonard consciously burns Jimmy's photograph and drives off in his car. He has Teddy's license plate number tattooed as the second attacker, leading to his eventual death.
Question: Leonard gets a tattoo of what object?, Answer: John G's license plate Question: Who does Leonard meet with?, Answer: Teddy Question: In what order are color sequences are shown?, Answer: Reverse-Chronologically Question: who meets teddy?, Answer: Leonard meets Teddy. Question: Why did Leonard kill the attacker?, Answer: Because he raped and strangled his wife. Question: What is the profession of Leonard Shelby?, Answer: An insurance investigator Question: What disturbs Leonard?, Answer: Anterograde amnesia Question: what is the polaroid photograph of?, Answer: dead man Question: who swaps clothes with Jimmy?, Answer: Leonard swaps clothes with Jimmy Question: Who burns Jimmy's photographs?, Answer: Leonard Question: who strangles to him?, Answer: Leonard strangles him