Chen Nian and Liu Beishan appreciate each other, and their meeting only stems from an accident. Chen Nian came home from school and met Liu Beishan, who was beaten. Chen Nian wanted to call the police, but was caught by the hitter and forced to kiss Liu Beishan. Perhaps it was the first time someone offered to help, and Liu Beishan followed Chen Nian, because no one had ever helped himself. Liu Beishan was very grateful to Chen Nian, but Chen Nian didn't like Liu Beishan so much at first, because they were from two different worlds, but later, because Chen Nian was bullied by Wei Lai, she had to ask Liu Beishan to protect herself.
However, Wei Lai bullied Chen Nian while Liu Beishan was away, and made videos for fun. Afterwards, Wei Lai worried that Chen Nian's alarm would affect her future and asked her forgiveness. Chen Nian said that he didn't want to see Wei Lai again. Wei Lai kept talking in Chen Nian's ear and didn't feel that he had done anything wrong. Chen Nian accidentally killed Wei Lai in a rage. In order to let Chen Nian go out and realize his dream, Liu Beishan charged Chen Nian with murder, but Chen Nian surrendered after the college entrance examination.
In the end, Chen Nian and Liu Beishan both went to prison. After serving their sentences, they were relieved and had a new life. There was love between Liu Beishan and Chen Nian. At first, we appreciated each other and depended on each other, and then we gradually developed feelings for each other. This feeling cannot be erased. Although the film doesn't say whether they are together in the end, I believe they must be in love.