A retired professor of American origin lives a solitary life in a luxurious palazzo in Rome. He is confronted by a vulgar Italian marchesa and her lover, her daughter and her daughter's boyfriend, and forced to rent to them an apartment on the upper floor of his palazzo. From this point on his quiet routine is turned into chaos by his tenants' machinations, and everybody's life takes an unexpected but inevitable turn.

Fred works for an insurance company as a computer engineer. He is bored with enduring the trials of his shrewish wife, so, after using actuarial tables to calculate the most common means of death, he cleverly prepares the family bathroom and brings about her demise. For a while he is content with his new freedom, but then he recognizes that a friend is in a similar situation.

In wartime France, Pharmacist Eliane begins a torrid affair with her shop assistant Armand, but she soon becomes dominated by him. He demands more and more from her, humiliating her and putting her family at risk.

Fabio Testi is an undercover cop doubling as the bodyguard (hence, “Gorilla”) of a cantankerous middle-aged industrialist targeted for extortion.