In 1983, the Kings County Sheriff's department, in the area around Seattle, realize they have a serial killer in the community. Det. Dave Reichert is put in charge of the case but the killer, who has been dumping bodies in the Green River area, proves to be elusive. Reichert has the FBI develop a profile of the killer but the body count keeps rising. By the mid-1980s, it includes over 40 women killed or missing, all believed to be the Green River Killer's victims.When the remains of victims are found in neighboring Oregon, the FBI formally enter the case and soon make an arrest only to be forced to release their suspect after much ballyhoo. While the investigation continues, teenager Helen 'Hel' Remus grows increasingly disaffected with her life. She lives with her divorced mother and is raped by one of her mother's boyfriends. On her 18th birthday, Hel moves out and takes to prostitution to survive. By this time, everyone knows about the Green River killer but it doesn't stop Hel from getting into a pickup truck with a potential client.

With few new leads, the investigation into the Green River killer drags on. The killer has either reduced his frequency of killing or, as some believe, may have moved to a new location. or even died Budget cuts lead to cuts in the task force until it's reduced to Dave Reichert and Faye Brooks. Dave refuses to give up however and reviews boxes and boxes of evidence. Using a tip he received from serial killer Ted Bundy, Dan is certain he's found a pattern with one of the suspects they've previously interviewed but still has no physical evidence that ties him to the murders. Not until 2001 does the science of DNA matching give him the proof that he needs to make an arrest.