When Cody Mack is called to the principalÕs 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.

With CodyÕs archnemesis, Headmaster Farley, banished from the school, Cody should be celebrating . . . but something is bothering him, eating at him . . . literally gnawing on him. Dark forces are on the rise at Splurch Academy and Cody Mack isnÕt sure which side of the battle heÕs on.

Headmaster Farley's back and he's ready for revenge, but an unexpected visit from his estranged sister brings monstrous results as she takes over Splurch Academy. Forced to retreat to his laboratory, he hatches a plan to reclaim the school. Meanwhile, Cody Mack and the other boys are pitted against their new classmates-the girls of Priscilla Prim Academy for Precious and Proper Young Ladies.

It's a squid invasion! The boys uncover an old forgotten swimming pool hidden away below the floor of the school's gymnasium?-and below the surface they discover a whole undersea world that might just provide them with a way to finally escape from Splurch Academy. However, they soon realize that the pool is overflowing with evil monstrous squids.