Fred, Daphne, and Velma help Shaggy and Scooby clear their names when they're framed for stealing a bunch of Japanese swords with a curse that attracts a Samurai Warlord Ghost and encounter the ghost at the same time.

It's Halloween and the gang gets set out for trick or treating. At their friends the Johnsons' house, they learn that there is a real ghost living there. The ghost is a sweet one or so they think. The ghost of a long dead pirate comes demanding the Johnsons move away. The real ghost asks the gang to help save his house.