Leonard Shelby (Guy Pearce) suffers from a special mental condition that prevents him from forming new memories, but the memory of his raped and murdered wife burns as strongly as ever. As Leonard searches for the truth about his wife’s death, he is aided by a man called Teddy (Joe Pantoliano), who offers him clues and tidbits but has motivations of his own. Leonard must figure out just how much he can trust Teddy, and the equally mysterious Natalie (Carrie-Anne Moss), all the while struggling to keep information from escaping his sieve-like mind as he closes in on his wife’s killer.