The hotel fails an inspection, largely because of Zack and Cody's bad behaviour. The inspector ends up running the hotel very strictly, so the twins try to get her fired to get the staff's jobs back and make up for what they did.
London's father is furious about her non-attendance at school and transfers her to a Catholic girls' school. Maddy's unhappy as it's her school, and London's unhappy because the school has a plaid uniform.
A security specialist hijacks a nuclear submarine with the intention of bombing a U.S. target if his ransom demands are not met. Harm must thwart the attack and rescue Bud, who is aboard the submarine.
The boys arrange a free cruise holiday for themselves and their mother. She's delighted, but they haven't told her it's only free if she sings on board every night.
Lois is placed in danger when a man from her past arrives in Metropolis to lay claim to an ancient Irish crown.