A ghost tricks Polly into entering a bottomless pit. The old haunted house is actually a hideout for Riff Raff and Mooch. The two villains use a combination audio and video devices to create the ghosts and other supernatural horrors to scare away nosey visitors from their hideout. Underdog- sentenced to twenty years for his reputed participation in the theft of the gold- hears Polly's calls for help from the phony haunted house. He escapes from jail and heads for the old house and saves the Polly from the bottomless pit. While searching the old house, the pair find Riff Raff's phony ghost machines and his red paint cans. Underdog now knows who is behind the theft of the gold bricks and heads for the state line to stop the two crooks.