When Fred’s favorite adventurer, Dr. Rick Spartan, begins teaching the biology class at Crystal Cove High School, the gang gets to meet him. After Fred and Spartan have a long conversation, Spartan invites the gang to have dinner at his house. At Spartan’s house, he shows Fred his latest discovery, a cursed shrunken head. But when its headless body appears and threatens to pursue Spartan until he dies, the gang decides to help Spartan to find a way to break the unending curse. Meanwhile, Shaggy and Velma try to rekindle their relationship, but Velma no longer has the same feelings for Shaggy that she once had.