After experiencing setbacks in her life, a middle-aged woman bravely turns back time to restart her youth as if she were twenty again.
He Pei Jin is a woman who once had her whole life ahead of her, but she exchanged the best years of her youth and gave up her career to become a model housewife. As her marriage crumbled, she realizes that she is left with nothing. Nevertheless, she doesn't blame nor hate but strives to set her life on the right track to chase after the precious moments that she has lost. She returns to school to become her son's schoolmate and starts anew to fulfill her dreams one at a time.
Xu Jing Shu of second-year class 1 is a cold person who doesn’t talk a lot, and if it weren’t for the teacher constantly sending her out of math class as punishment, she may as well be invisible. That is until the transfer student Chu You Ning shows up. He’s attracted to her candy-sweet smile, so on certain afternoons, one could see the god of studying, Chu You Ning in the upstairs independent study room teaching math to Xu Jing Shu.
Adapted from novel, Her Smile So Sweet (她的微笑像颗糖) by 休尹 (Xiu Yin).