- Qin Zhao: A left-handed consulting detective, skilled in microexpression analysis and criminal profiling. Traumatized by the "Rainy Night Beheading Case" three years ago, he always wears a bronze snake-shaped pocket watch.
- Lin Shen: A former battlefield medic turned forensic pathologist and toxicology expert. He carries a bone scalpel and can determine time of death to the exact minute.
- Shen Nanxing: A passionate detective with an extraordinary memory who never forgets a single detail from any case. He is always thinking with a cold cigarette between his teeth.
Told from the first-person perspective of Lin Shen, the assistant.
