After graduating from high school where she was a boarder, Reine Ducasse decides to settle down with her rich father Louis in his luxurious apartment. She has just begun her studies in history and has a good friend, Frédéric, a medical student who wouldn't mind being more than just that. Around her, strange fellows attract her attention. Who is Philippe, allegedly Louis's stockbroker? And what about Marguerite who presents herself as her father's former secretary? Even more puzzling is the video cassette she finds in her father's place, showing young motorbikers distributing bundles of banknotes. Some time later, Charles, one of the bikers appearing on the video, rings the doorbell: he is wounded.

Inspector Leroux is investigating the owner of a contemporary art gallery Helen Duvernet who is suspected of being involved in trafficking of stolen paintings. He is both intrigued and attracted by the young woman, follows her everywhere and finally falls in love...