In the hot summer of 2019, the 18-year-old Chen Zihao and Yang Yuhang meet. Chen Zihao, who's often at the bottom of the class, accidentally discovers that the handsome Yang Yuhang, the topper of his class, is his secret pen pal of the past two years. Upon the chanced encounter, the two of them take the time to talk about everything and gradually, their relationship becomes closer than ever. But with the looming college examinations right around the corner, how will they go on from here?