Bai Jinxi's name is Su Mian. In the case five years ago, there was an accident. In the second season, Xin Jiayou explained that the seven-member group died because of that incident and the team was fragmented. Similarly, Han Shen and Bai Jinxi (proved in the second season) who participated in the incident also lost their memories. At that time, there were signs (Han Shen's investigation direction) that Bai Jinxi was not the former Bai Jinxi, that is to say, this person named Bai Jinxi may be another person who was replaced. The fact is, Su Mian sneaked into the group of seven as an undercover, and Bai Jinxi is Su Mian's cousin, who looks similar and can't tell her dress. Then the group of seven dragged Bai Jinxi to the camp here, and Han Shen's companions found that "Su Mian" really killed someone, but Bai Jinxi did it, and Bai Jinxi died. The Group of Seven arranged for Su Mian to turn her into Bai Jinxi, but the Group of Seven knew her identity.