Sixteen-year-old high school student Su Zaizai grew up in a good family environment and became a person who doesn’t easily get obsessed with boys and doesn't blindly follow others. On the first day of high school, Su Zaizai disdainfully dismissed her good friend's obsession with boys but had an instant face-slapping moment when she encountered the aloof and cool Zhang Lurang. Su Zaizai fell in love at first sight with Zhang Lurang and decided to take immediate action, transforming herself into a clingy follower behind him. However, behind his seemingly outstanding academic performance and privileged family background, Zhang Lurang is a "contradictory" person who appears to be quite confident on the outside yet constantly doubting himself on the inside. Due to the presence of his genius younger brother, Zhang Luli, Zhang Lurang is constantly compared to him by his mother. For over a decade, Zhang Lurang 's life has been like living inside a thick shell. He’s introverted and speaks little. He looks composed and polite but keeps everyone at a distance. However, after meeting Su Zaizai, light pierces through Zhang Lurang’s life in the “shell”. The encounter between the two brings about a wonderful chemical reaction in each other's lives.