A crime suspense story set in a forensic laboratory where specialists work to uncover clues from seemingly insignificant bits of trace evidence. The story begins when Sawaguchi Nonna, a rookie forensic researcher, meets Mano Reiji, the man who solved her parents' murder case.

The manga centers on homicide detective Hiroki Dan, the son of a former police superintendent general, and who seems to be on the fast track to career success. He maintains a hidden identity as a serial killer responsible for more than a hundred murders of people he deems beyond the reach of the law.