Publicist Claudio and homemaker/choral teacher Helena have been married for many years, but they don't understand or respect each other's feelings or viewpoints. Claudio sees Helena as a shopper and "little teacher of a choral" and Helena sees Claudio as insensitive and rough. On the night before Claudio's 50th birthday, Mars, Earth, and Jupiter are aligned and during a quarrel at home, Claudio and Helena say "If I were you..." at the same time. When they wake up the next morning, they have switched bodies and each must face the other's difficulties in the agency, in the school, and with their friends.