The news of a visit from Mr. Tipton gets the employees excited (and reminiscing) about their good deeds as to who deserves a possible bonus… but when they find out Mr. Tipton is in a bad mood and will fire someone, all fingers point to Carey because of the boys' mishaps, but Zack & Cody come up with a plan. In the end Mr. Tipton fires Muriel not knowing she retired 2 years ago.
Zack and Cody offer to bring their mother on a week-long vacation to the S.S. Tipton, staying in the King Neptune Suite, which overjoys Carey. However, they neglect to tell her that the only way they could afford the vacation is for Carey to be the cruise ship's singer, although Carey soon finds this out herself. Since Carey does not want to work during her vacation, she offers to pay for her room herself, although the only room she can afford is the "Sardine Suite" (storage room). Annoyed by the few privileges she has from this, she finally agrees to sing, although she falls asleep in the sun and gets sunburn, no longer able to perform. Zack and Cody then perform in her place and do a good job, and get an encore. Meanwhile at the Boston Tipton, London is hosting a 24-hour telethon during her "Yay Me!" broadcast, while raising money for the homeless/hungry through phone pledges. However, a blizzard occurs, which prevents any of London's guests for her broadcast to get to the hotel (since the roads have all been closed). Therefore, they are forced to improvise, which include Mr. Moseby jumping through a hoop like a dog, Maddie and London performing a ventriloquist act, and London spinning plates. However, they soon realize that their internet connection has been lost for over twenty three hours and that all their performances had been for nothing. Instead, they decide to give the left-over food from the Tipton to the food shelter once or twice a week.
Zack tries out for the high school basketball team but realizes there's some stiff competition, the kind he didn't face in middle school, and worse yet, the giant, in-your-face Coach Little (Michael Clarke Duncan). Meanwhile, when they're rejected as cheerleaders, Cody and London form their own cheerleading squad with the help of Mr. Moseby.
Zack and Cody befriend Travis, a kid whom they rope into helping them impress their dates. They then bail on Travis and go out with their dates, but lets Travis go with the girls instead. Maddie finds a stranger's phone whom she thinks is her crush (because she and the stranger have many of the same interests, which she found out on the lost phone). At the end, the owner of the phone was an old man, but Maddie takes an interest in the old man's grandson.
Tony Hawk checks into the Tipton; Maddie and London has a crush on their fencing instructor. While Zack and Cody are doing their science project, the problem is that Cody has a fear of germs, and when Zack makes a mistake when analyzing a germ from the kitchen and thinks it's a toxic type of black mold, the rumor spreads through the hotel and everyone starts panicking. Cody gets over his fear after he realizes that he can't go skateboarding with Tony Hawk wearing an anti-germs suit.
Maddie is back and is not getting along with Nia, while Estaban is not getting along with Patrick, and the rest of staff aren't getting along either. So, Mr. Moseby hires a professional to help the team get along. Meanwhile, when Zack causes some customers to leave, he and Cody schedule a bug convention at the Tipton to make it up to Mr. Moseby. However, due to his fear of bugs, he accidentally releases the bugs into the Tipton.
Cody searches for a summer job, and finds a "help wanted" sign at the local mini-mart. When the owner realizes Cody is friends with London, he will only hire Cody if he will set him up on a date with her. Zack discovers he is the smartest student in his summer-school class, all the other kids make fun of him.