Zack and Cody have two pet rats as a science project. Mr. Moseby gives the twins tickets to a Red Sox's game to get them away from the hotel. Then a hotel inspector seizes control of the Tipton, because of Zack's mistake. London has a dog party for Ivana and Maddie has to plan.

London develops a crush with the son of a rival hotel owner, of which Ilsa is the the manager. Zack and Cody bake cookies to be served at a ball held at the Tipton.

Mr. Moseby and the Tipton Staff is challenged to a bowling competition, by its rival, Ilsa and her team. Zack is the star bowler for the Tipton, but ends up having to be replaced due to getting grounded. Zack's replacement must overcome his emotional scars, due to a past bowling incident.