Xiu Hao (Cha Tae Hyun) and Xiu En (Song Hye Kyo), who have known each other since junior high school, are both in high school. Xiu Hao's grades and appearance are average, but he looks very simple and kind. The beautiful Xiu En is the dream lover of all the boys in the school, but in fact, Xiu En already has a crush on someone, that person is Xiu Hao. The two often came together afterwards, which made many boys who like Xiu En very jealous, and the very angry boys even beat Xiu Hao together. But he was innocent and never knew that Xiu En liked him. Xiu En then expressed her admiration for Xiu Hao through a recorded email. After hearing Xiu En's true confession, Xiu Hao also felt the feeling of first love. The two began to fall in love and lived very happily. Under the arrangement of their classmates, the two spent the most unforgettable day on a small island. What shocked Xiu Hao was that Xiu En had been hiding the fact that she was seriously ill from her boyfriend.