An American playwright living in Rome consults a quack psychiatrist to combat his fears of balding and save his failing marriage.

Andrea, the only son of a rich publisher, is a neurotic young man obsessed by his mother. He is dominated by uncontrollable impulses and suicidal fantasies, while his regressive behaviour makes him lonely and frustrated. Incapable of having normal sexual relationships, he spies on his stepmother's adulterous affairs and is obsessed by Carol, a young American girl he secretly films (even when she's making love with her boyfriend), and whom he clumsily courts. Finally, Andrea wins Carol over but is still tormented by the fear of losing his own private world of memories and macabre games...

B 501, a newly developed controller for missiles, has disappeared despite the strict surveillance. Phillippe Tissout is sent by his boss to Paris to take over the case.