Billy, an immature and irresponsible man-child, is the heir to a wealthy family's hotel empire. His father is set to retire and doubts Billy's competence to take over the business. In a desperate bid to prove himself, Billy strikes a deal with his father: he will repeat grades 1 through 12 within 24 weeks, spending two weeks in each grade. Winning this challenge would demonstrate that he possesses the dedication and intelligence necessary to run the family business.

As Billy embarks on his unusual educational journey, he humorously navigates the challenges of being an adult among children, forming unlikely friendships and encountering various comedic obstacles. His main adversary becomes the ambitious and conniving executive, Eric, who seeks to take control of the hotel chain for himself. As Billy advances through each grade, facing both academic and personal growth, the stakes rise and complications intensify, leading to a final showdown that will determine who gets control of the family empire.