Silvia Heredia, since her arrival to Madrid is staying at her best friends' house, Mary. Her aim is to work as a secretary of a famous novelist. But at night the house is full of people and they confuse her with the owner of the floor. A series of misunderstandings makes her meet Ricardo Ariaga, the musician whose opera "Life begins at midnight" is about to debut. Ricardo convinces Sylvia to act as his wife. With a "rented" child they try to be the perfect family of a lonely old man.