The central twist of "Better Days" is the revelation of how the bully, Wei Lai, actually dies. After a particularly brutal assault where Chen Nian's hair is cut and she is humiliated, Wei Lai, fearing that Chen Nian will go to the police, confronts her. During their heated argument on a long flight of stairs, Chen Nian shoves Wei Lai, who accidentally falls to her death. This crucial detail reframes the narrative from a simple case of a victim getting revenge to a tragic accident with devastating consequences.
Xiao Bei, in an ultimate act of sacrifice, decides to take the blame for Wei Lai's death to protect Chen Nian's future. He stages a fake assault on Chen Nian to create a narrative that he is a violent criminal who killed Wei Lai and then attacked Chen Nian. This plan is designed to absolve Chen Nian of any involvement, allowing her to take the gaokao and go to college. The police detective, Zheng Ye, suspects the truth but struggles to prove it. He eventually tricks Chen Nian into confessing by lying that Xiao Bei has been sentenced to death. Her emotional breakdown reveals their pact, and ultimately, they both agree to serve lighter sentences. The ending reveals a time jump of several years. Chen Nian is now a teacher, and in a poignant final scene, she is seen walking a young, distressed student home, with Xiao Bei following closely behind, still fulfilling his promise to protect her. This ending suggests that while they have paid their debt to society, their bond and the echoes of their past trauma remain, but they have found a way to create their own "better days" by protecting others.