Hapless young Bill Denny (Farley Granger) and his bride, Kate (Shelley Winters), stumble into big trouble when Bill takes in a cute little dog. The stray happens to be a courier for the mob, and the canine's presence in the Denny home brings underworld violence to the couple's front door. While Bill tries to figure out why dead mobsters are suddenly everywhere, the police are also investigating. Will the pooch's presence lead the police to think that Bill and Kate are criminals?