After serving live bait to a sea monster living in a lighthouse, Sammy and Scooby swear not to eat Scooby Snacks any more. Deprived of their favorite delicacy, the duo devours a mountain of burgers in their favorite restaurant, the Malt Shop and earns by accident a paid trip to Hollywood! There, while visiting the old Brickton Studios, Scooby Gang discovered that the ruined studios were threatened by the ghost of the actor of classical horror films Boris Karnak who appears in the form of his old roles: The Chevalier Sans-Tête, the Mummy and the Zombie. And to top it all, the cast and the staff of the film that represent the last chance of the studios all fled from fear. The Scooby Gang decides to act with Sammy as an actor, Vera as cameraman, Daphne as star and Fred as director.