Mike Pritchard's daughter, Emily, is kidnapped by a sex trafficker, who delivers a concussive blow to Mike's head during the abduction. The brain trauma endows him with the ability to detect the scent of a girl's soul, the olfactory equivalent to seeing a person's aura. His obsession with finding Emily, as well as his burden of guilt, lead to estrangement from his wife. Now a loner and a private investigator, Mike plunges into the cesspool of organized crime in Washington state's urban centers where he rescues trafficked girls, delivers vigilante justice, and hunts for clues to Emily's whereabouts. When a clue to the abductor's location unearths in Spokane, Mike faces a heart-wrenching dilemma-to either risk the lives of other trafficked girls or else never learn what happened to his long-lost daughter.