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).