17-Sai Kara Yarinaosu Propose17-sai Kara Yarinaosu Propose; 17歳からやり直すプロポーズ; Marriage proposal to start over from 17 years old.; 17살부터 다시 시작하는 프로포즈; 从17岁开始的求婚; 從17歲開始的求婚

*I wish I had liked you when I was a high school student * Osamus girlfriend refused his proposal with these mysterious words. After that, in an accident, he time-leaps back to his high school days. He was trying to find her and make her fall in love with him again, but when he met her she had a twin sister! ??