Three years after a traumatic experience on a Mediterranean cruise, Vincent Durieux lives a vagrant life, hunted by the mysterious client of an unscrupulous private investigator. One day, he discovers the lifeless body of a friend, murdered, and immediately becomes one of the many suspects of Lieutenant Groussard, the lead detective. Finding the culprit proves difficult and becomes even more complicated when Vincent disappears. He then enters a true nightmare, simultaneously threatened by a ruthless killer and pursued by the police.