Gomez's brother, Pancho, is staying with the Family while Gomez goes to a lodge meeting in Tombstone, Arizona. Gomez is jealous of his brother, who once courted Morticia. Halloween is nigh, and Pancho tells the legend of Cousin Shy, who distributes gifts and carves pumpkins. Actually, Gomez has been lured off by crooks, who have bugged the house in order to steal the Family fortune. Lafferty, the boss, sends Mikey to investigate. Wednesday (Senior) is home from music academy, where she studied the piccolo (she breaks glass with it). Pugsley (Senior) is home from Nairobi medical school, where he's training to be a witch doctor. Mikey panics and flees after treading on Kitty Kat's tail. The crooks have a fake Gomez and Morticia to help in their plans, along with two strong-arm goons, Hercules and Atlas. Gomez returns home for the Halloween party and trimming the scarecrow.

Lafferty poses as Quincy Addams (from Boston) to get in. He has his men tie up Gomez and Morticia and his doubles take their places, confusing Pancho, who' s still got the hots for Morticia. Lurch scares off the thugs and terrifies the assistant crook. Fester, trying to be nice, puts Lafferty on the rack. Lafferty tries to escape through the secret passage and steps on Kitty Kat's tail. When the police arrive, they surrender. The Family is then free to celebrate Halloween happily.