Policemen Bienvenido and Chato rent rooms in a house owned by Doña Lupe, an elderly woman in financial trouble. Doña Lupe mistrusts the men, but allows them to stay, as she needs the money. When they change the locks and begin smuggling suspicious materials into the house, Doña Lupe decides to take drastic measures.<ref name="filmblog"/><ref name="DVDVerdict"/>