On a hot summer night, a watchful neighbor locks eyes with an intruder and unwittingly alerts the police to a vicious crime scene next door: a lavish master bedroom where a man lies dead. Next to him, his wife is bleeding out onto the hardwood floor, clinging to life. The victim, Adam Grant, was a well-known San Francisco prosecutor --- a man whose connection to homicide detective Valerie Hart brings her face-to-face with a life she’s long since left behind. Adam’s career made him an easy target, and forensic evidence points towards an ex-con he put behind bars years ago. But while Adam’s wife and daughter grapple with their tragic loss, Valerie uncovers devastating clues that point in a more ominous direction.

When she’s called to the murder scene, the last thing San Francisco Homicide detective Valerie Hart is expecting is for Katherine Glass to walk back into her life. Six years earlier, revulsion and fascination had gripped the nation in equal measure, as Katherine had been convicted on six counts of Murder One. But the freshly mutilated corpse in the ground-floor apartment bears all the hallmarks of Katherine’s victims. And then there’s the note, with its chilling implications, addressed to Valerie. To stop the slaughter, Valerie must ask Katherine to help her decipher the killer’s twisted message. But that means re-entering the pitch-black labyrinth that is Katherine’s mind, and this time Valerie isn’t so sure which one of them will survive.

When the two strangers turn up at Rowena Cooper's isolated farmhouse, she knows instantly that it's the end of everything. For the two haunted and driven men, it's just another stop on a long and bloody journey. For San Francisco homicide detective Valerie Hart, their trail of victims has brought her from obsession to the edge of physical and psychological destruction. But the murders at the Cooper farmhouse didn't quite go according to plan. There was a survivor, Rowena's 10-year-old daughter, who now holds the key to the killings.