Pac, Spiral, and Cyil go to a special Halloween dinner at the Haunted Transylpacia Castle. Little did they know, the host Dr. Pacenstein and his sidekick ghost Eeghost have a few tricks up their sleeves including Dr. Pacenstein swapping bodies with Pac. Fortunately Dr. Pacenstein's neighbor, Count Pacula, helps Spiral and Cyil as they try to hunt down Dr. Pacenstein in Pac's body while trying to keep Pac safe from Betrayus and Dr. Buttocks who want to destroy Pac once and for all. The teens sure have their hands full trying to save Pac while also dealing with witches, bats, gargoyles, and giant spiders on All Hallows' Eve!