A unique online crime live broadcast aroused Jiang Yunan, who was dedicated to solving strange cases, and volunteered to be investigated. However, Lin Yang, a misdemeanor police officer who emerged halfway, became Jiang Yunan's right-hand man in later handling the case.
Jiang Yunan, who faced a mysterious murderer for the first time, suffered from a lack of network technology and turned to Zhang Lin, a hacker police officer who had been wanted by five countries and then was recruited. The arrogant Zhang Lin competed with two police officers who crossed the line unconventionally. Due to their similar temperaments, they quickly formed a police triangle and devoted themselves to cracking the case of online criminal live broadcasts.
However, based on clues, the three people learned that the identity of the mysterious murderer turned out to be a person who died in an accident four years ago. Facing the murderer hiding in the dark, the three anxious people had no idea what to do.
However, under the full investigation of Jiang Yunan and the others, the mysterious murderer's methods escalated step by step, and even Jiang Yunan's ex-girlfriend Li Muchen was involved.
They faced a series of murder cases that evolved from live broadcasts of kidnappings, old cases that were dusted by time, hateful murderers who became victims one by one, and criminal challenges that escalated step by step. How can the iron triangle of the police force meet the challenge of facing the mysterious murderer?
Can they save each other when faced with the murderer of what appears to be a victim? Can the broken relationship between Jiang Yunan and his ex-girlfriend Li Muchen be repaired? Can the mysterious murderer who controls everything behind the scenes be brought to justice by the Iron Triangle? What is his purpose? How to decide between law and morality in the end?