Leonard Shelby was an insurance investigator who, after being attacked by a burglar, suffered from anterograde amnesia.
The attack
Leonard's Story
Shelby was from San Fransisco, and married Catherine Shelby. The two lived together, and he would often tease her about re-reading her favourite novel. In the course of his job, Leonard was called out to investigate Sammy Jankis, who had developed short-term memory loss due to a car accident. He suspected something strange about Jankis, so ordered a doctor to carry out some conditioning tests. When these did not produce results, Leonard ruled that Jankis's condition was mental, not physical, and he was not eligible for an insurance payout. Leonard got a promotion, but Sammy's wife came to his office distraught, asking if there was a chance Sammy could regain his memories. Leonard told him he thought that Sammy should be physically capable of doing so - he found out later this caused Mrs Jankis to go home and trick Sammy into killing her.
Later, one night Leonard woke to find his wife's side of the bed cold. He heard muffled screams coming from the bathroom, so drew a gun and burst in. He found an intruder raping his wife under a shower curtain, so shot the man, but another assailant hit him from behind, knocking him unconscious and causing anterograde memory loss. His wife did not survive the assault. Leonard got a hold of a police report, and set off to track down his wife's killer.
Teddy's story
Teddy claimed that Sammy Jankis never had a wife, and was faking his amnesia condition. When Leonard investigated him he exposed him as a con man. After the attack took place, Leonard's wife survived, but could not cope with Leonard's condition. She tricked Leonard into killing him by injecting her with too much insulin, and then Leonard was put into a mental institution. At some point Leonard got out, believing that his wife had been killed in the assault, and Teddy gave him the police report to help track down the killer. They eventually found him, killed him, and Teddy took a picture of Leonard. However, Leonard did not remember, and set out again to find the killer, not remembering he had already found him. He removed several pages frm the police report, to give gimself a puzzle he could never solve. Teddy followed Leonard from town to town, in order to limit the damage he was doing.
Hunting John G.
The phone call
At some point later, Leonard arrived in a town and checked into the Discount Inn. Burt, on reception, noticed Leonard taking a picture of the place, and called his boss Jimmy Grantz. Jimmy met Leonard and came to know him as "the memory man". While in his room, Leonard received a call from Teddy, and began to explain about his condition and Sammy Jankis. While doing this, he began preparing to tattoo a fact onto his leg: "Fact 5: Access to drugs". However, Teddy convinced him that John G. (the name of his wife's killer) was a drug dealer. Leonard changed his tattoo accordingly and wrote it on his leg.
Leonard then discovered a tattoo on his arm stating "never answer the phone". Panicking, Leonard hung up and barricaded himself in his room. Someone then slipped an envelope under his door, containing a picture of Leonard smiling and pointing at his heart. Reluctantly Leonard took the man's call, and agreed to meet him downstairs. He went to the lobby and met Teddy, who claimed to be a police officer. He took a photo of Teddy, writing his name and number on the bottom. Leonard then set off for an abandoned barn, where John G. would be waiting.
Jimmy Grantz then arrived, and Leonard beat and strangled him to death. While transporting him to the basement, Jimmy whispered the words "Sammy Jankis". Thinking he had killed the wrong man, Leonard panicked and ran outside. He then saw Teddy who had just arrived, and demanded to know what was happening. Teddy explained that Leonard had already got his revenge, and now he just needed someone to believe was John G. in order to give his life purpose. Leonard refused to believe it, and wrote "Don't believe his lies" on Teddy's photograph. He then wrote a note that Fact 6 would be Teddy's license plate, and took Jimmy's car and clothes. He drove off, leaving Teddy alone.