Zack and Cody are graduating from middle school – or are they? When Cody finds out that he defeated his girlfriend for the coveted valedictorian spot, Zack is troubled to learn that he earned a spot in summer school. Rather than disappoint his parents, Zack devises a scheme to walk across the stage and "receive" his diploma. Meanwhile, Maddie decides to be a camp counselor but gets a little more than she expected with the girls she is to oversee.
Cody goes searching for a summer job and comes across a "help wanted" sign at the local mini-mart. When the manager realizes that Cody is friends with London, he will only hire Cody if he sets him up on a date with her. Meanwhile, Zack feels what it's like to be Cody in school when he discovers that he's the smartest one in his summer school class and all of the kids make fun of him.
Zack has finished summer school and needs to find a job so Arwin hires him to help around the hotel. When a position opens up at the local market, Zack decides to take the opportunity but doesn't know how to tell Arwin.
Meanwhile, London gets swimming lessons from the lifeguard at the Tipton.
When Zack and Cody see a shooting star, they both wish that they had superhero powers. Their wish comes true and they learn that superheroes must face a villain – in the guise of Mr. Moseby -- who wants to turn all kids into mini-adults.
Cody gets Zack a job at a mini-mart and starts bossing him around; London's afraid of introducing Lance to her friends because she fears what they will think of him.
A manager at a rival market challenges the boys to see who can bag items faster. While Cody is out to win, Zack prefers to hang out with London and Nia, Moseby's niece.
Cody tries to impress a girl from school by telling her she can have her birthday slumber party in London's hotel suite while she's out of town. Of course, London returns home early.
The boys invite lonely Arwin to dinner but then can't get him to leave; London is dumped by Lance and then tries to win him back.
Maddie teams up with classmate Antonio and auditions for the role of Sharpay and Ryan Evans in their school's stage production of "High School Musical". Cody and Antonio land the roles they're hoping for, while Maddie loses the role of Sharpay to London, who proves that performing is not one of her strengths.
Zack and Cody attend their first day of high school and meet London, who is going to public school for the first time.
Zack tries to negotiate a better contract for his mom as the Tipton's nightly singer; London loses her science tutor so she asks Cody to help her with a project, but Nia also wants his help and she tries to bribe him with concert tickets.
Zack and Cody accidentally let a monster-like robot, Arwin, loose in the hotel. Meanwhile, London hosts a Halloween costume party.
Maddie returns from a trip to Antarctica, and Nia refuses to give Maddie her old shift back; Moseby schedules a team-building seminar for the Tipton staff; Zack books an entomology convention at the hotel and accidentally knocks over some crates, releasing hundreds of bugs throughout the hotel.
A new violinist joins the school orchestra and promptly begins flirting with Cody's girlfriend, sending Cody into a fit of jealousy. Elsewhere, London tries to learn the ropes of the hotel business by shadowing---and frustrating---Tipton employees.
A problem arises when Zack and Cody both use their dad's apartment for a date at the same time. London gives Esteban lessons in being rich now that his family has seized power in his native country.
Zack overuses an online video game. Meanwhile, Cody helps London produce a Web show called 'Yay Me' which stars London Tipton.
Cody develops a fear of germs while he and Zack work on a science project; skateboarder Tony Hawk checks into the Tipton Hotel. London and Maddie learn fencing from an instructor who they fall in love with and fight over.
In order to impress their dates, Zach and Cody convince a sophisticated man to cook up a gourmet dinner and perform a Japanese tea ceremony. Meanwhile, a found cell phone may be the link to the perfect match for Maddie.
Zack, now on the high school team wants to quit basketball when he realizes he is no longer the star player. Cody, London, Nia, and Barbara create their own “misfit” cheerleading squad after being rejected by the mean girls' squad.
Zack and Cody get into trouble once again and Carey grounds them to their room for the weekend. Cody is anxious because he is not able to produce this week’s episode of “Yay Me” for London. The boys devise a plan to escape the confinement of their suite. When London dicovers she will not have a producer she hires Maddie, but not everything goes according to plan.
Zack and Cody surprise Carey with a much needed cruise vacation on the SS Tipton. The boys barter for the trip by promising Carey will sing for their passage, but they do not tell Carey. When Carey refuses to sing they get down-graded accommodations. Maddie convinces London to turn her “Yay me” show into a 24 hour telethon to raise money for charity...a blizzard keeps their guests from showing up and the girls Mr. Moseby and some other of the Tipton employees must fill in.
Songs: Cody and Zack martin -- We're Gonna Have A Good Cruise
The news of a visit from Mr. Tipton gets the employees excited (and reminiscing) about their good deeds as to who deserves a possible big bonus…when it is determined that Mr. Tipton is in a bad mood, they realize one of them is about to be fired…all fingers point to Carey because of the boys mishaps at the hotel.
Songs: Carey, Zack and Cody Martin -- Three Little Maids