An unexpected tip-off convinces Gabriel and his team to launch a risky mission designed to catch the killer in the act. But as pressure mounts from all sides, Gabriel begins to push away those closest to him. When Gabriel publicly denounces the acid murderer during a press conference, the killer's sights turn towards him and the tension ratchets up as the hunter becomes the hunted. Meanwhile, Elaine confronts the demons of her past. As the dark, hidden lives of those closest to him begin to be revealed, Gabriel is forced to face up to his changed self and the indelible mark left on him by the killer. Struggling to cope with the effect this case has had on his life, Gabriel swears renewed investigative vigour. However, just as he does, Gabriel uncovers a shocking secret that cuts straight to the heart of his family.