 Rodrigo Catano seeks to impose in his family a Porfirian order. One day a door to door salesman, Roberto del Hierro, comes into the house to sell an American vacuum cleaner from the "Bright O Home" company. Maru, Mr. Catano s daughter, watches Roberto while he demostrates the new machine. Roberto leaves and says he will come back to explain Mr. Catano about the vacuum cleaner. Mr. Catano is very upset because a man has been in his house without him been present. Nevertheless, with fast and inteligent talk, Roberto sells him the vacuum cleaner and, later on, a refrigerator. Maru is captivated by Roberto and they fall in love. Mr. Catano is furious when Roberto announces to him he will marry Maru.