Memento

Essentially, Memento is a straightforward revenge flick with Guy Pearce's Leonard tracking down the man who raped and murdered his wife. But this standard plot comes with an ingenious twist. Brain damage Leonard sustained during the attack has left him with the memory of a goldfish. He forgets conversations he had two minutes ago. He doesn't know if the man sitting next to him is his best friend or sworn enemy. He can't even remember if the bottle of Scotch he's clutching is to get him pissed or to bash over the head of his assailant. What assailant? Exactly.

His confusion intensifies when he gets caught up with drug dealers who readily abuse his condition. He's developed a system of cataloguing events and characters from his investigations with Polaroids, charts and tattoos (allowing for repeated exposure of the Pearce torso) but these are just as susceptible to manipulation, and finding the real killer becomes increasingly tricky.

Christopher Nolan's audacious conceit necessitates the plot to run backwards, starting with Leonard killing the man he thinks is guilty and slowly revealing whether or not he picked the right target.