Saul and Mônica return to São Paulo after three years and find his family's colonial mansion abandoned, inhabited only by his old nanny, Bá, and his brother, Domício.
Two friends live without knowing a most awkward situation: each one is the lover of the other's wife. Jealous, they hire the same private eye to track their women, who, of course, gets very embarassed by the situation, especially when the two couples rent rooms at the same hotel.