中学生に戻った俺は学園一の美少女の自殺する過去を変え未来に戻ったら彼女と結婚していました。

Itsuki Irie, a virg*n and a deadbeat freeter (a term referring to someone who only works low-paying part-time jobs), is living a miserable life, burdened with debt, shuttling back and forth between his rundown apartment and the convenience store where he works. His days are hellish, spent working to repay his debt. One day, he is nearly hit by a truck. In that moment, Itsuki recalls the only regret in his life—the time in middle school when he confessed his feelings to a girl named Kotori Shiina, only to be brutally rejected.

When he wakes up, he finds that he has time-leaped back to his middle school days. Standing before him is none other than Kotori Shiina, the most beautiful girl in school. Just as before, Itsuki confesses to her and is rejected again.

But then, Itsuki remembers—this confession is what caused Kotori to start being bullied, eventually driving her to su*cide. Determined to change Kotori’s tragic future, Itsuki Irie begins to take action to prevent her from ending her life.