两名有着共同痛苦回忆的调查员，联手侦办一桩神秘谋杀案，案件证物包括一块四万多年前的石刻。他们很快发现，彼此共同的过去就是破案关键…。

Mid-August in Paris (the title is a date: August 15) in a sunny, quiet apartment a young woman talks, thinks, reflects about herself, everyday life and little events in a long, uninterrupted monologue. The camera pictures her and her gestures in long, fixed shots moving around the rooms, the space, the light and shadows of a summer day.