陈念(周冬雨 饰)是一名即将参加高考的高三学生,同校女生胡晓蝶(张艺凡 饰)的跳楼自杀让她的生活陷入了困顿之中。胡晓蝶死后,陈念遭到了以魏莱(周也 饰)为首的三人组的霸凌,魏莱虽然表面上看来是乖巧的优等生,实际上却心思毒辣,胡晓蝶的死和她有着千丝万缕的联系。 一次偶然中,陈念邂逅了名为小北(易烊千玺 饰)的小混混,随着时间的推移,心心相惜的两人之间产生了真挚的感情。小北答应陈念在暗中保护她免受魏莱的欺凌,没想到这一决定引发了一连串的连锁反应。负责调查胡晓蝶死因的警官郑易(尹昉 饰)隐隐察觉到校园里的古怪气氛,可他的调查却屡屡遭到校方的阻挠。When it is time for the Chinese gaokao, the entire country comes to a standstill. For nearly ten million high school students, this two-day national college entrance exam will determine where and if they get to study. It is not uncommon for the fates of entire families to hinge on the results. Like so many others, Nian has been single-mindedly preparing for the exam, at the exclusion of everything else and all alone. A classmate has committed suicide and she has become the target of relentless bullying. Meanwhile, fate brings her together with small-time criminal Bei and the two of them seal a pact. Derek Kwok-cheung Tsang's intense melodramatic thriller paints a bleak picture of an oppressive society, in the guise of a gripping fairy-tale love story.