Mario Marani is a well-respected lawyer in late 70s Milano. He and his wonderful wife Francesca have an intense high social life. But Mario has a problem. He is obsessed by bad thoughts (cattivi pensieri); he is always concerned about his wife, thinking continuously to be betrayed by her. It is a nightmare, every time Mario sees Francesca talking to one of their friends immediately starts to see her and him in an hot affair. Jealousy and suspects increase and increase, till their life cross with a young man hidden inside their flat.