Gakkou no Kaidan

A boy named Yukihiro Kanba enrolls at Tengurihama Academy after being adopted by his uncle. One day, he encounters Yuuko Kokonoe, who runs past him and disappears down the stairs. Later, when Yukihiro meets the gymnastics club, which tries to recruit him, Yuuko intervenes, leading him to join an unofficial club known as the "staircase club." The club engages in stair racing, an activity with a negative reputation among students. Initially hesitant, Yukihiro eventually grows to enjoy the thrilling nature of the club's activities and chooses to become a member.