Sakura, Saku.

A mysterious boy comes to Saku Fujigaya's rescue when she falls in on a train, but he leaves before she can thank him. After this experience, Saku never ignores strangers in need of help to emulate the boy who helped her.

Saku would like to thank the boy who helped her, but all she has is a note signed "Ryosuke Sakura." She discovers that...