Sol had gotten into an accident and had no will to live a life. However, a phone call from Sun Jae, the vocalist of the group Eclipse, gave her hope and comfort. Since that day, she has become Sun Jae's fan. Years have passed, and Sol goes to Sun Jae's concert. But a few hours later, Sun Jae is found dead. And then, Sol goes back to 2008, when Sun Jae was still alive.

Sol is confused about the situation, but one thing she knows is that she must save Sun Jae. She finds out that she can't directly explain the future. To save Sun Jae, she decides to become friends with him, but it's not easy to become friends. Meanwhile, Tae Sung is curious about Sol who changed all of a sudden. And Sun Jae is also bothered by Sol who appeared in front of him from nowhere.

Sun Jae wins the gold medal at the competition, and he decides to confess his feelings for Sol. But due to unexpected events, it’s not as easy as it seemed. Sol thinks that she has changed the future, but Sun Jae gets hurt during practice. Sun Jae decides to quit swimming, and it makes Sol heartbroken. Sol tries to comfort Sun Jae, and Sun Jae finally confesses his feelings for her.

Sol is back in 2023. She couldn’t save Sun Jae, but she found out that she did make some changes in the past. She manages to go back in time again, but things have turned out strangely while she was gone. Sol is officially dating Tae Seong, and Sun Jae feels confused and betrayed about Sol. He wants to keep a distance from Sol, but Sol keeps showing up. Meanwhile, Sol gets lost on her way home.

Sun Jae saves Sol just in time. Sol realizes how precious her life is and tries not to miss out on many things. Tae Seong feels jealous of Sun Jae who seems close to Sol. Meanwhile, the vocalist of Tae Seong's band can't come to the band contest, and Sun Jae sings for the band. Sun Jae gives the prize to Sol as a gift, but Sol is upset because he sang in a band which she wanted to prevent from happening.

Sol breaks up with Tae Seong, thinking he only dated her to avoid the girl who likes him. Sun Jae tries to be cool with Sol so he can win her heart, but it’s not easy for him to hide his feelings. Sol tries to avoid her accident that will happen to her in the future. Meanwhile, Tae Seong gets in an accident and gets hospitalized. At the hospital, he runs into someone unexpected.