Prueba de lealtad

T1, E1: Eugenio manipulates Fernanda, who killed her abusive stepfather and avoided jail thanks to him, forcing her to do his bidding to take revenge on the Del Pino family. As secretary of the Del Pino Corporation, Fernanda seduces Alfredo, her half-brother, and infiltrates his house. She drugs Ana, the rebellious eldest daughter, with the help of a psychiatrist, but Ana catches her murdering Maria Laura, Alfredo's wife. In addition, Fernanda accuses Elisa, the youngest daughter, of an affair with Francisco, the grandson of nanny Manuela, getting Alfredo to beat Francisco and fire Manuela, eliminating who he considers an obstacle.