Herman discovers he's the new lord of Munster Hall in England. The family sails to Britain, where they receive a tepid welcome from Lady Effigy and Freddie Munster, who throws tantrums because he wasn't named Lord Munster. An on-board romance had blossomed between Marilyn and Roger, but on land Marilyn discovers Roger's family holds a longstanding grudge against the Munsters.
The film begins with the Munster family making a visit to the wax museum. They take a picture of themselves standing next to their wax replicas. When the family leaves, the statues in the museum mysteriously come to life and begin wreaking havoc across the city. Herman and Grandpa are then arrested for various crimes they did not commit and try to clear their names in time for the Halloween celebration at the Munster home.