London, Zack, Cody and Mr. Moseby set sail on the S.S. Tipton for their semester at sea. London convinces her roomate to leave the ship so she can have a room to herself. Cody finds himself sharing a room with Woody, who is very messy, and Zack shares a room with Bailey, who is a neat freak. Nobody knows that Bailey is a girl who disguised herself as a boy in order to gain a position on the ship after she found that there were no more vacancies for girls. Zack and Cody agree to switch roommates, but Zack changes his mind after he finds out that Bailey is a girl. After everyone else eventually finds this out Bailey is allowed to stay, filling the position vacated by London's ex-roommate, and Bailey becomes London's new roommate. This is the last straw for London and she escapes to Parrot Island via helicopter.

When the S.S. Tipton makes a special trip to pick up London from Parrot Island, Bailey, Moseby and Woody find themselves in jail because all the parrots left for Seal Island after Tipton Industries cut down all the trees. It's up to Zack and Cody to get them out of it but Zack and Cody end up in jail along with the others, and Bailey has to use her pig, Porkers, to rescue them. Zack and Cody fight for Bailey and Zack lets Cody have her after finding out about her ex-boyfriend Moose and seeing she has too much "baggage".

Bailey is mad that London is hogging all the space in their cabin, so she makes up a "Sea Snark" attack, but later feels guilty and tells her the truth. Meanwhile, when Zack uses up both his and Cody's meal cards buying things for all of the girls on the ship, they go broke. To make up for it, Moseby puts them to work. Because of that, Zack thinks that Cody should win the yo-yo contest for its $1,000 prize, but Cody finds himself up against the pro, Johan Yo.

Zack has a crush on a cute passenger named Violet, but must deal with her wealthy "boyfriend" Ashton and snooty mother who will do anything to keep Zack and Violet apart. Meanwhile, Cody referees an intelligence test between London's dog Ivana and Bailey's pet pig Porkers. The episode includes plot elements from the 1997 film Titanic, where Jack was framed for stealing the "Heart of the Ocean" necklace.

London and Bailey are on a mission to prove that Miss Tutweiller is dating Mr. Moseby after overhearing a conversation between the two. Meanwhile, Zack convinces Cody to sneak out after curfew to catch the Starlight Follies show on the ship. When they finally make it past the security guard and into the show, they become convinced that their teacher, Miss Tutweiller, is one of the showgirls by seeing her heart shaped anklet in the show, and during class, so Zack sends Bailey and London undercover as two showgirls to find out.