Ashita, Hadashi De Koi. Tomorrow, When Spring Comes. (Dengeki Bunko) [Light Novel]

[Machine Translation] On graduation day, I was thinking back on my dull high school life. My grades were not so good, I had given up on my dreams, and my girlfriend and I had spontaneously broken up. And now she was a national musician. I had become a resident of a completely different world. But then one day. My ex-girlfriend, Futato Chika, disappeared, leaving behind a suicide note. I was stunned... I found myself time-released into the past on the day of the entrance ceremony. In this world, can I save Erto? No, that's not enough. This time, I hope we can be equals. So that I can be side by side with her. I will do my best to rewrite even my own three years! This is a love story of redoing youth, starting from graduation.

卒業式、俺は冴えない高校生活を思い返していた。成績は微妙、夢は諦め、恋人とは自然消滅。しかも彼女は今や国民的ミュージシャン。すっかり別世界の住人になってしまっていた。だがその日。元カノ・二斗千華は遺書を残して失踪した。呆然とする俺は...気づけば入学式の日、過去の世界にタイムリープしていた。この世界でなら、二斗を助けられる?...いや、それだけじゃ駄目なんだ。今度こそ対等な関係になれるように。彼女と並んでいられるように。俺自身の三年間すら全力で書き換える!卒業から始まる、青春やり直しラブストーリー。