Yuuichi Katagiri has battled financial hardships his whole life but has learned to stay content and positive thanks to his close circle of friends. To keep a promise he made to them, Yuuichi saves up enough money to join them on the school trip. But when the gathered money mysteriously goes missing, suspicion falls on two of Yuuichi's friends: Shiho Sawaragi and Makoto Shibe, who were in charge of collecting the payments. Although innocent, Shiho and Makoto take responsibility for the failure to protect the money when no one else comes forward.