Guy Pearce (the uptight ass-kisser in L.A. Confidential ) plays Leonard, a young, guilt-ridden insurance investigator. He's pursuing his the man who raped and murdered his wife, but he has a bizarre inability to form new memories; if he happens upon an important clue, then orders a sandwich or walks around the block, he won't remember what he learned. He calls it a short-term memory disorder. So he frantically tattoos himself with clues, reminders and warnings and scribbles notes on hurriedly-shot Polaroids so he can identify people he already knew, and remember details he's already discovered.
Lenny's life is further complicated by a couple of people who appear to be friends (Joe Pantoliano, now playing the evil Ralphie on The Sopranos, and Carrie-Anne Moss) but who it gradually becomes clear might (or might not) be manipulating Leonard for their own murky reasons.
Leonard, anxious, even desperate, lives in a continuous fight with the outside world, constantly trying to orient himself and make snap judgements about his evolving reality. He is particularly haunted by his callous handling of an insurance claimant who suffered from the same memory disorder. Through Leonard's guile, his company refused the man's genuine claim for compensation. His tattoos and pictures remind of him of what he has done, and help him keep track -- he thinks -- of his wife's killer. He is continually forgetting his interactions with other people, remembering and re-remembering.
Nolan makes things considerably more challenging by running most of the story backwards, so the audience is essentially faced with the same problem Leonard has -- struggling to stay oriented, keep up, check his pictures and notes, and figure out what information is real. His mind replays people,words, memories and clues over and over again, a kind of thinking reflected in the fractured structure of the movie itself. This is an amazing editing and writing feat, weakened only by a mildly cheesy, anti-climactic ending. And the film noir feeling is enhanced by the seedy L.A. neighborhoods and motels the story runs through.
This movie demands a lot of its viewers. Leonard lives in a dizzy, whirling present tense, even as he is constantly in need of repetition, reinforcement and reference.
Memento is like a nightmare from which Leonard and the audience can't awaken. Soon enough, we realize that nothing can be assumed to be as it appears. Leonard is like a fly stuck in flypaper. As much as he struggles, he can't break free. The effect is riveting, Leonard's predicament genuinely frightening. You leave the theater trying hurriedly, along with everyone else, to patch together clues, portents and explanations before you forget them -- just like Leonard. Plan to see this movie at least twice to grasp what you missed the first time.