Zack and Cody do a science project dealing with rats. Mr. Moseby gives them tickets to go see a baseball game, and Zack decides to take the two rats with him. When they return, an evil hotel inspector comes to inspect the Tipton. The rats escape from Zack's pockets and run wild through the Tipton lounge. Furious, inspector decides that Mr. Moseby is not a good enough manager, and sends Mr. Moseby packing. The inspector becomes the new manager of the Tipton and begins to make everyone mad. Zack goes to Mr. Moseby's apartment to persuade him to return to the Tipton, but Mr. Moseby refuses. Zack and Cody plan a perfect scheme to bring Mr. Moseby and making the hotel inspector look bad. While London is throwing a dog poker party, Zack and Cody invite a cat convention to the Tipton, and soon all the dogs are chasing the cats throughout the hotel, making a huge mess. Zack, Muriel, and Esteban had called Mr. Moseby to come and help them, and he quickly has the hotel back in order. In the end, Mr. Moseby becomes the new manager of the Tipton, and the hotel inspector is forced to leave the Tipton. Meanwhile, London was throwing a dog poker party and had Maddie dressed up in a dog costume. After the party was over, Maddie ends up playing poker with the dogs.