Luo Weizhao’s team identifies a suspect, Zhang Donglan, who is connected to a high-profile group and the SID chief. Pei Su, with his own ties to the case, undergoes questioning.

An anonymous tipster, Chen Zhen, implicates a drug ring in his sister’s death. Tension escalates when the victim’s mother confronts Zhang Donglan after his release.

A raid on a nightclub uncovers new evidence. A crucial clue from a surveillance camera refocuses the investigation.

A new case involving a missing girl echoes a cold case from 16 years ago. Luo Weizhao revisits the father of a past victim for leads.

The investigation uncovers new truths about a cold case, and two new interns, including Pei Su, join the SID