Two unlikely students from contrasting backgrounds join forces to start their own business after a thwarted summer vacation plan leads to an unexpected lesson in finance. The story follows Ritsuki Tanikado, a rambunctious and imaginative fifth grader in Class 1 who dreams of going to Japan Hero Land, an amusement park. His hopes are crushed when his parents explain the family cannot afford the trip. While fantasizing about money raining from the sky during his school cleaning duties, Ritsuki is approached by Kujyaku Uechi, the wealthy heiress to a famous beverage company who has an enormous allowance and a devilish demeanor. Rather than simply giving him money, Uechi proposes they go into business together.

The central conflict arises from Ritsuki learning that there is no easy method to obtain money. Uechi teaches him to break down the total cost of the trip into entry fees, transportation, food, and souvenirs, framing it as an exchange of services. Their first goal is to earn the school's cleaning award, a prize for the most diligent student, which would prove to Ritsuki's parents that he has earned the trip. With Uechi's guidance, Ritsuki gamifies the chore of cleaning by turning it into a live action role-playing game with level-up charts and party members, a strategy that draws disapproval from his strict class representative, Yumeho Mifune, who favors traditional methods.

After receiving the award, Ritsuki discovers his parents still cannot afford the trip. Refusing to give up, he learns to budget by eliminating excess expenses and sells handmade goods and recyclable crafts on the online marketplace Mercari. Uechi explains terms of service, supply and demand, and the importance of accuracy and honesty in business, framing each lesson with fantastical metaphors and comedic exaggeration. As the series progresses, Ritsuki and Uechi expand their operation from earning pocket money to transforming mundane school tasks into fun, engaging experiences for their entire grade. Uechi defines their company as being in the business of making school work enjoyable, and Ritsuki dons a costume to pitch their services to the whole student body.

The narrative takes place in a contemporary Japanese elementary school, focusing on the fifth-grade classroom and the surrounding grounds where students perform janitorial duties. The homeroom teacher, Kotani sensei, provides guidance and introduces real-world obstacles such as teacher disapproval and financial limitations. The series is structured around short, educational arcs that demystify corporate concepts, including budgeting, asset assessment, and marketplaces. Ritsuki ultimately learns to shift his perspective from what his parents can do for him to what he can do for his family, growing from a daydreaming child into a proactive problem solver who applies business logic to everyday challenges. The story concludes after a short serialization, finishing with the fifth volume.