Protagonist: Shen Yan, a former criminal police officer and consultant in criminal psychology and forensic evidence analysis. He excels at spotting flaws in "impossible timelines."
Partner: Li Shen, captain of the municipal criminal investigation team. A man of action, he complements Shen Yan.
Killer's codename: Watchmaker.
The central mystery: At every murder scene, there is a clock that has been deliberately stopped. Its hands point to a time that is neither the time of death nor the time the body was discovered, but a crucial moment in an unsolved case from 20 years ago.
