The bloody formula on the wall predicts the next murder.
Parachuted criminal profiler Gu Xiang is forced to prove herself - she can "see" the murderer's thoughts.
Captain Lu Mingzhou didn't believe it at first, until she found the body of the second victim with just a string of numbers.
But this is just the beginning.
The mysterious number "719" was left at each scene, and each deceased person was related to a top-secret experiment twenty years ago.
Her missing brother, Lu Mingzhou's father who died in the line of duty, and her own strange "synesthesia" all point to the same name - "the abyss."
When she received a warning from the mysterious "Lighthouse", she realized: the murderer was screening and testing.
And she was the next target on their list.
When the sophisticated serial killer, the "guardian" lurking in the dark, and the "liquidator" wandering around the edges appear at the same time, she must solve the ultimate crime that uses the entire city to experiment before the "final activation day" on July 19.
Because this time, what she wants to hunt is not the murderer, but the creator hidden behind the rules.
