The bud of bittersweet first love takes bloom!

A mysterious boy comes to Saku Fujigaya’s rescue when she falls ill 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 Fujigaya would like to thank the boy who helped her, but all she has is a note signed “Ryosuke Sakura.” She discovers that a boy at her high school, Haruki Sakura, has an older brother named Ryosuke. She asks Haruki to deliver her thank-you letter to Ryosuke, but he refuses!
目立たず、いてもいなくても変わらない存在だった藤ヶ谷咲（ふじがや さく）。咲は、ある日電車で「桜」という名前の人に助けられたことをきっかけに、自分も困っている人をほっておかないと心に決める。時は流れ、入学した高校で「桜」と呼ばれる男の子に出会って…!?　ピュアで、切ない恋のつぼみが今、開きはじめる――！