Leonard Shelby suffers from severe anterograde amnesia after his wife's murder. He is unable to form new memories and wakes up each day not knowing how he got there. He takes many photos and tattoos himself with notes to try to piece together what he is doing and who to trust as he searches for his wife's killer. The film depicts his fragmented perspective through disjointed scenes and tangents in a way that accurately reflects the experience of living with anterograde amnesia.