In a crime-heavy district of Xizhou, the body of a young man is discovered. Special Investigation Division (SID) officer Luo Weizhao arrives at the scene, where suspicions arise linking this to previous drug-related cases. The scene also draws the attention of Pei Su, the young president of the Pei Group.

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.

The suspect's alias and tragic past come to light. Luo Weizhao takes a more personal approach to uncover the truth.

While celebrating a birthday, Pei Su notices a mysterious gaze following a child — hinting at a new threat.

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.

A girl vanishes during Pei Su’s birthday dinner. The team connects her disappearance to a survivor of a similar past case.

Clues lead to a chilling diary found with human remains. A twisted relationship and dark secrets emerge.

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

A corporate heir is kidnapped. Family secrets and power struggles within the Zhou Group surface.

A shocking package from the past revives questions about a suspicious death. The SID follows new leads.

A series of deaths and a fire point to a larger conspiracy. Pei Su and Luo Weizhao uncover secrets buried in Pei’s childhood home.

As suspects flee, more details about the Zhou Group’s shady rise to power are exposed.

A car explosion puts Pei Su’s life at risk. The SID closes in on a shadowy figure.

Pei Su recovers in the hospital and begins to trust Luo. A mysterious visitor brings insight into Pei’s past.

Luo receives a cryptic letter from his late mentor. A new case begins as five students disappear.

A mutilated body is found. Surveillance footage identifies a long-wanted criminal from the "327 Case".

A student reveals a hidden hierarchy of abuse within a boarding school.

Interrogation reveals manipulation and cover-ups. A victim tried to expose systemic violence before his death.

Trust is tested as Pei Su speculates he might be the "Purifier". Luo Weizhao affirms his belief in Pei.

The team traces surveillance footage to uncover the criminal’s hideout.

A drone-supported raid leads to the discovery of a planted bomb — an ominous escalation.

Old injustices resurface. Luo Weizhao uncovers secrets tied to the notorious Seine Riverside case.

The team discovers the star witness was impersonated. The SID suspects an internal leak.

A bug is found on an SID member. Pei Su and others suspect a high-level traitor.

A repressed memory reveals a key player in past cases. A shocking disappearance changes the game.

All forces converge at an abandoned mansion — the site of a past murder. Loyalties are tested.

The final confrontation forces a life-or-death decision. Pei Su and Luo Weizhao face the ultimate moral challenge.