While at a farm picking vegetables for Thanksgiving dinner, Daphne, Velma, and Fred are turned into pumpkin-headed monsters and Scooby and Shaggy must help them.
Scooby-Doo and his friends at Mystery, Inc. head to the beach for some fun in the sun, but a sea monster might ruin their day if Scooby and Shaggy can't find the monster, and their missing friends.
Scooby-Doo and Shaggy find themselves in the school theater and not knowing that it is a rehearsal of the school play happening on stage believe something sinister is about to befall their friend Daphne.