In a garage under Place Vendome, firemen find a burnt corpse behind the wheel of his car. The cops identify Philip Roquin, an accountant at a jewelry store. Being told about the tragedy, his family and employer's testimonies differ: the latter hasn't heard of Philip in two weeks while his wife tells the cops he has been in a car accident. Having found the killing was perpetrated following a kidnap and ransom, Jo tracks back Philip's trail to discover Lisette, a woman he was having an affair with, which might have led him to his death. In a race against time to save the next kidnapping victim, the investigation leads Jo to a prison where Lisette had spent time and a warden who has strange relationships with the inmates.