Sister Bertrille is looking after Pepe, a chimpanzee, as a favor to Dolores, one of Carlos' girlfriends. Pepe's arrival at the convent coincides with a rash of thefts in the neighborhood, thefts of small, rather insignificant trinkets. The latest theft is of Captain Fomento's watch right in the convent. Yes, the thief is Pepe. The captain thinks that it is someone in the convent. Sister Jacqueline, who finds the stolen items in Sister Bertrille's closet (Pepe's hiding place), reports such to the Reverend Mother and based on Sister Bertrille's behavior, Sister Jacqueline and the Reverend Mother believe Sister Bertrille suffers from kleptomania. Sister Bertrille is oblivious to Pepe's thieving ways until she sees him take off with a candlestick. As Sister Bertrille chases after Pepe, Sister Jacqueline, the Reverend Mother, Captain Fomento and Sgt. Salazar chase after Sister Bertrille. It isn't until Dolores returns to retrieve her thieving pet monkey that the truth is revealed to all.