When Cody Mack and the boys uncover an old, forgotten swimming pool hidden below the floor of Splurch Academy's gymnasium they think it may provide them with an escape route, but the pool is overflowing with evil, monstrous squids.
Escaping the Splurch Academy infirmary using stolen keys, Cody Mack and friends prepare for Halloween and try to figure out Cody's dreams about a giant beetle that seems to be turning him into a monster.
When Headmaster Farley's estranged sister takes over Splurch Academy, Cody and the other boys are pitted against their new classmates, the girls of Priscilla Prim Academy for Precious and Proper Young Ladies.
When Cody Mack is called to the principal's office yet again, he finds something far worse than detention awaiting him: Splurch Academy, a frightfully sinister boarding school for disobedient children run by a group of monstrous teachers.
