The protagonist is thirty-year-old Leonard who is trying to find out who murdered his wife. The situation is complicated by the fact that while he can remember things that happened before the murder, he can’t recall what happened five minutes ago. Leonard knows about his disability and so he takes a camera with him everywhere he goes, writing down all his thoughts relating to the investigation. His body even serves the purpose as he has the most important observations tattooed onto it. As the story progresses it becomes more and more difficult to tell who is a friend and who a foe, who is a victim and who is the murderer. The only thing certain is that we know less and less as time goes by. The lapse in Leonard’s memory corresponds to the style of filming: Black-and-white images alternating with colour, flashbacks and repeated scenes work to create a kaleidoscope which forces the viewer to share in the same confusion and uncertainty as Leonard does.