When the new aqua lounge is flooded, Mr. Moseby vows to expel the student responsible for the mess. Although Mr. Moseby assumes Zack is the culprit, Cody, Bailey (who had just returned from Kettlecorn), and Woody all believe they are each responsible for the disaster for different reasons. Meanwhile, Marcus leaves the ship to make a Broadway musical based on his hit song ”Retainer Baby.”