Three years ago, Chen Yuxuan handled the "dark key" unsolved case, in which the core algorithm of a multinational technology company was stolen. There was also no trace at the scene. The surveillance system failed bizarrely, leaving only a vague and twisted key imprint. The case was eventually ordered to be sealed by superiors. While pursuing key clues, his partner Liu Jin was seriously injured in an "accidental" car accident and became a vegetative state. Liu Jin's warning before the accident still rings in his ears: "Some locks cannot be opened. If they are opened, they cannot be closed."
Lin Man's death was no accident. The mysterious drawings, encryption equipment in her hand, and the key emblem that highly overlaps with the "Dark Key" case all point to a secret hidden in the shadows of the city. Chen Yuxuan knew that the unsolved case three years ago had never been resolved, and Lin Man's death was just a signal that someone would open the "lock" again. He teamed up with He Qingxi to investigate Lin Man's social circle and unusual whereabouts, cracking the secrets in the encryption equipment, and reorganizing the clues of the "Dark Key" case, trying to connect all the pieces.
As the investigation deepened, they discovered that behind Lin Man's death, a transnational conspiracy to steal technological secrets was involved, and Liu Jin's "accident" that year was no accident. Erased surveillance, professional encryption techniques, mysterious key emblems, every clue hides a murderous intention. When the technical department was about to crack Lin Man's mobile phone, and when the clues of the old and new cases gradually intertwined, Chen Yuxuan realized that they were touching a secret that could subvert everything, and the murderer in the shadow was already ready for the next attack. This three-year pursuit of the murderer is destined to be thrilling at every step, and they have no way out.
