Plot Summary:Returning from her ordeal in Mexico Nikki seeks out her friend fellow pathologist Sally Vaughan for support but three days later Sally disappears after a contentious visit from colleague David Cannon who is anxious to buy her lab. Thomas invites David to join his team after family man Livtar Singh is found dead in a reservoir, a suspicious death made to look like a suicide but Nikki finds David's behaviour odd and follows him as he meets a woman in a pub. As evidence suggests Livtar's infidelity Sally's blood-stained phone is traced to the remote farm-house of Angus Merrick but he is wounded in a police shoot-out and Sally is not there.
Thomas and Jack are surprised to see Nikki back at The Lyell, the disappearance of her friend Sally forces her to face her back after her harrowing experience in Mexico.