It is every night of a school trip inside the boys' dormitory at a Japanese high school: a space where male students shed their inhibitions and devolve into something resembling monkeys. The story begins when a boy named Fujimura visits an open-school event and falls instantly in love with a cute student he meets there. Switching his first-choice school to enroll there, he moves into the four-person dormitory. When he opens the door to his new room, he is greeted by the sight of a male classmate standing in his underwear and striking a pose. Worse, Fujimura quickly discovers that the object of his crush is not a girl but a boy, and that the two of them have been assigned to the same room. What follows is a day-to-day record of life inside a room where fantasy, desire, pride, and misunderstanding collide at every moment. The four roommates navigate the raw, unfiltered realities of teenage boyhood—obsessive grooming rituals, shameless boasting, rivalry over trivial matters, and the constant tension between social image and actual impulse. Through Fujimura's perspective as the relatively normal newcomer, the manga observes how the other boys behave when no adult is watching: conversations veer between absurd debates and sincere confessions, and every small event escalates into an operatic farce. The setting of the dormitory itself becomes a character—a pressure cooker of testosterone where each resident's personality is laid bare, and where the chaos of communal living reveals both the ridiculous and unexpectedly touching aspects of male adolescence.