In a large eastern American city, a fiend is loose, painting mustaches onto the faces shown on billboards and posters. This fiend is a wacky Daffy Duck whose compulsion to paint mustaches has no bounds. He is chased by police officer Porky Pig on the city walkways, in a subway station, and atop a building with a large billboard. Daffy manages to paint a mustache on anyone he encounters. He takes special delight in doing so to Porky, as many times as he can. Porky finally catches Daffy, and the mischievous mallard is brought to court, where he is acquitted by a jury of mustached Jerry Colonnas!