Plot Summary:The \"Custard Cup,\" a cluster of tenements surrounding an oval courtyard, is home to the widowed Mrs. \"Penzie\" Penfield, who cares for the building and her three adopted children. Among the colorful tenants are Frank and Gussie Bosley, a secretive couple involved in a counterfeiting operation. When Alderman Curry hosts a boat excursion for his constituents, Frank accidentally sets the vessel on fire while attempting to destroy the phony bills in his pocket. After the passengers are rescued, Penzie is accused of passing counterfeit money. A detective proves her to be an unwitting victim, and the Bosleys are apprehended.