The film is based on the short story Butterflies by Ian McEwan. A little girl has drowned in a nearby canal. A 19-year-old man, who lives in the same inner-city neighborhood, is the sole witness. Although he has made a statement to the police of everything he saw, the father of the little girl wants to talk to him today. The young man still has a few hours before the meeting, and lots of time to kill on this dreary Saturday. The events of the past days spring forth in his memory.