All aboard for mischief and mayhem as the twins Zack and Cody board SS Tipton to attend the Seven Seas High School. Cody's roommate is even messier than Zack and Zack's is a girl in disguise.

London's unhappy at having to attend school on board and runs away to Parrot island. London's friends try to bring her back but get themselves in trouble. A pig comes to the rescue.

Zack has to work after buying gifts for all the girls on board, and Cody enters a yo-yo competition in the hope that winning will impress Bailey.

Violet's snobbish mother and rich would-be boyfriend Aaron try to keep Zack away from her by pretending he has stolen her valuable necklace, called The Kidney of the Sea.

Zack and Cody sneak out after curfew to see the ship's cabaret show Starlight Follies. They are convinced one of the dancers is their teacher Miss Tutweiler.

The ship's struck by lightning and Cody finds himself stuck in the same day repeatedly. He wants to use the time to let Bailey know how he feels about her but it is not as easy as he thought it would be.