A psychiatrist is found handcuffed to the bottom of his swimming pool. The hunt is on for a young blonde woman present at the crime scene. During the investigation, Cherif and Briard are accompanied by the actor Tom Duval, who is studying their investigating methods for a future role...

After witnessing a murder, Cherif is knocked down by a car. Suffering from amnesia, he has forgotten the last five years of his life. Was he deliberately run down? Whatever the circumstances, the investigation becomes difficult when the key witness cant even remember his partners name.