Mario is married to Carla, a rich businesswoman. She's off to Geneva for two days, he has a tryst with Monique, a Swedish air hostess. Carla's flight is canceled, so she heads home about to catch Mario en flagrant. Mario's salvation is Enrico, an old school mate and hapless salesman who shows up to beg Mario to buy toilets so he won't lose his job. Mario signs an order in exchange for Enrico's posing as Monique's husband. Carla invites them to stay overnight and join a business dinner party catered by Enrico's wife, Matilde. Enrico spends the evening trying to avoid her, Mario spends it chasing the willing Monique, and Carla wants to close a deal.