Police find a man dead at his home in Los Angeles. Nothing suggests foul-play but elements of the victim's house show that something is deeply wrong. Meanwhile, in Glasgow, DI Rachel Narey is searching for a missing young woman -- and the man she suspects of killing her. When a feed broadcasting the slow and painful death of a final victim is discovered, these two cases become linked. There's no way to identify him. No way to find him. No way to save him. Not without the cooperation of a killer. And the only way he will cooperate is if he can watch him die.