The modern heroine Jun Yue confessed to her same-sex classmate Sicheng but was rejected. In order to satisfy Sicheng's wish, Jun Yue decided to hold a solo concert for Sicheng on Valentine's Day, so she prepared day and night, spending countless thoughts, just for Sicheng to smile... The ending was not that the lovers finally got married, but at the cost of Jun Yue's body. On the day of the concert, she was admitted to the Sixth Hospital of City B. The story begins here. Jun Yue's soul traveled through time and space, returning to the year when he was admitted to high school, and met "himself" at that time, but his modern soul was exchanged with a Taekwondo coach... So what will Jun Yue do? Make up for future regrets? Accompany and love your past self? What's even more incredible is that Sicheng also went back to the past, just to meet him or her... In the ending HE, Junyue will come back, but in another way.