The Munsters’ Revenge

The Munster family visits a local wax museum where the lifelike replicas secretly operate as robots. When the museum closes, the robots spring to life, terrorizing nearby citizens and stealing belongings. The family becomes entangled in the chaos that follows.

The next morning, police arrest Herman and Grandpa for theft at the Munster home. They manage to escape custody and steal the police chief's car, racing back toward the wax museum to clear their names. The escape sharpens the town's suspicions.

Herman and Grandpa hide inside after hours and deactivate the replicas, then pretend to be the robots to avoid detection. They uncover a hidden laboratory where Dr. Dustin Diablo hints at a larger scheme to rob the museum's treasures later. The discovery signals a bigger criminal plan behind the chaos.

The duo are taken by a moving van to a pizzeria, where they witness a suitcase of money changing hands between the owner and the scientist. The exchange reveals the scale of Dr. Diablo's operation. They are forced to sneak back home afterward.

Back at home, the Munsters meet Glenn, a rookie detective and the police chief's son, who Marilyn has recruited to help clear their names. They brief him on the laboratory and Dr. Diablo's plans. Glenn heads to the wax museum to search for the lab, only to find that the lab has vanished and the robots replaced.

Herman and Grandpa disguise themselves as waitresses and infiltrate the pizzeria, waiting for the owner to meet with an accomplice. They shadow the crooks back to the wax museum, then pretend to be the robots to eavesdrop on Dr. Diablo's plan to steal the pharaoh mummy's jewels on Halloween.

Grandpa formulates a plan to use a life rejuvenation serum on the mummy to bring him back to life and capture the gang, but the serum is missing in Transylvania. They resolve to retrieve it by heading to Grandpa's old laboratory. They board a plane to begin the journey.

They reach Grandpa's old laboratory in Transylvania, and Grandpa injects the serum into his former assistant Igor, reviving him and making him young. The revived Igor becomes a new ally as the danger from the pursuing crowd looms.

They return home just before Halloween, where relatives arrive to celebrate. Lily informs them that Marilyn and Glenn went to the wax museum but have not returned yet. The family braces for the night as the holiday approaches.

Herman and Cousin Phantom venture to the wax museum and find Marilyn and Glenn trapped inside a shatterproof container. Cousin Phantom belts out a high note that shatters the container, freeing them. They join Grandpa at the museum as the rescue unfolds.

Grandpa administers the rejuvenation serum to the pharaoh mummy, reviving it and giving it new vitality. Marilyn seizes Dr. Diablo's controller, rendering the robots useless and throwing the plan into chaos. Dr. Diablo presses on to claim the museum's jewels as the mummy rampages.

The mummy grabs Dr. Diablo, drawing the day toward a dramatic climax. The police arrive to restore order, and Glenn is vindicated by the events. The crowd at the wax museum cheers as the criminals are captured.

In a twist, Herman is revealed to be the mummy, a result of Grandpa giving the real mummy too much serum which aged it to three years old. The family reflects on the madcap events as order is restored and Halloween ends.