When Midori Nanami drops her wallet on her first day of high school, a boy helps retrieve it for her. Midori finds herself too slow to respond to his kindness, and before she can properly thank him, her savior walks away. Later, Midori learns that the boy she owes her gratitude to is Rei Ichijou, one of her new classmates.

Shortly after their classes begin, Rei stops showing up along with his friends, Yukinojo Ieiri and Chihiro Goshima. Midori discovers that the three boys are shrouded in shady rumors, but she can scarcely believe any of them. Would a bad person have helped her when they could have simply chosen not to?

When a careless slip-up leads to the school chairman finding out about Midori's job that she is not allowed to have, she is given an ultimatum. Either she quits her job and has her scholarship revoked, or she helps out the chairman instead—by persuading Rei and his friends to start attending school again.