Once a week, high schooler Shiori Miyagi pays her classmate Hazuki Sendai five thousand yen. The money buys her three hours of Sendai’s time and the right to give her any order she pleases. Miyagi belongs to the lower tier of the school’s social hierarchy, while Sendai sits near the top. The two never interact in class, but under this secret contract they spend after-school hours together in Miyagi’s room, away from everyone else.

The orders start small—playing games together, having Sendai feed her snacks, doing homework for her. But as the weeks pass, Miyagi’s commands become bolder: she asks Sendai to lick her feet, to kiss her skin. Sendai never refuses. Despite the intimacy they share, Miyagi insists they are not friends. Their relationship has no name. She is simply the one who pays, and Sendai is the one who obeys. Yet both girls begin to feel something more. When summer break arrives, Sendai suggests becoming Miyagi’s tutor so they can still meet during the holiday. The unspoken tension grows.

The story follows their final year of high school as the boundaries of the contract blur. Sendai brings up the idea of attending the same university, forcing Miyagi to confront the possibility that their arrangement might not end after graduation. Tensions peak in the spring when the original deal would naturally conclude. Instead of parting ways, they end up living together as roommates. With the five-thousand-yen excuse gone, they must find a new reason to stay connected, and the physical and emotional distances between them shift in unexpected ways. Later arcs cover shared birthdays, summer trips, school festivals, and Christmas parties, all while the question of what they truly mean to each other remains unanswered.

The story is told from alternating perspectives, giving insight into both Miyagi’s calculated curiosity and Sendai’s growing attachment. It is a slow-burn exploration of a relationship that starts as a transaction but gradually becomes something neither girl can easily define or let go of.