It's Halloween, and an elderly lady, Granny, is leaving a grocery store with her treats for the children. Minutes later, a masked crook disguises himself as an old lady, in clothes the same as Granny's, and robs the grocery store at gunpoint. The grocery store clerk believes he's been robbed by Granny, and inept police officers Daffy Duck and Porky Pig are assigned to the case. They antagonize the real Granny, who thinks they're juvenile delinquents in costumes and whacks them with her purse. And when they spot the crook and chase him to his hideout, he foils all of their clumsy attempts to gain access.