In Mexico, Rosario has a marriage of convenience without love with her husband Don Carlos Montero, who is a rigid and conservative antiquarian older and older than she. When Don Carlos punishes their son Carlitos without listening to him, the boy runs away from home. The engineer Julio Mistral finds Carlitos and brings him home, becoming a family friend. Soon Rosario and Julio fall in love with each other and have a love affair. Julio invites Rosario to move with him to Brazil with Carlitos but Don Carlos has a heart attack on the day that they would be traveling. Rosario sacrifices her true love to stay with Don Carlos and Carlitos. Many years later, Carlos and his younger brother Miguel are graduated in medicine and love the same woman, Luisa. They both plan to rent a building for a medical clinic and work together. Out of the blue, a notary that is friend of the family tells that Julio has died and left his fortune to Miguel that was chosen by Luisa. The envious and male chauvinist Carlos questions the fidelity of his mother and the biological origin of his brother.
—Claudio Carvalho, Rio de Janeiro, Brazil