A man living alone dies a bizarre, sudden death. The scene shows no signs of a struggle, and everyone believes it was an accident.
Trace consultant Lin Yan spots a carefully disguised murder based on just three tiny clues.
Behind it is a highly organized murder operation that targets loners who live alone, ensuring every crime leaves its perpetrators free of blame.
Following the clues hidden in the blind spots the killer left behind, Lin Yan digs deeper, leads his team across cities in pursuit, exposes a string of bloody cases spanning several years, and uproots the entire criminal network.
