The killer abducts an NYU student, who is taken to a derelict slaughterhouse and tied to a pole. The killer surgically removes a piece of bone from the student, leaving an open wound that attracts nearby rats. Amelia and Rhyme, again using the clues left by the killer at the scene of the previous murder, find the victim’s body which has been mutilated by rats. Amelia finds another scrap of paper and a piece of bone. The pressure of the tense investigation and bureaucratic challenges to Amelia and Rhyme’s involvement in the case begin to have serious impacts on Rhyme’s health and stability. Thelma, Rhyme's personal carer and nurse, reveals to Amelia that he intends to euthanise himself out of fear of seizures that could leave him in a vegetative state.