Ellis and Harper arrive in the town of Callorwell to investigate the disappearance of local detective Jenny Rawler. Leighton needs Ellis to control the case: the DCI of the station is off with stress, and the force recently arrested the head of a major criminal gang but bungled the case and had to let her go. Jenny's colleagues are indifferent to her disappearance, believing she left of her own free will, but Ellis - and Jenny's husband - feel something is amiss... More so when she learns that when Jenny disappeared, she was days away from submitting a complaint of bullying against her colleagues. Rife with a toxic culture, the station blocks Ellis at every turn forcing her to reach out to the enemy...