Cuando Nikki ve a la adolescente descalza Shannon Kelly siendo atropellada por un coche mientras huye de alguien, se queda con ella hasta que llega la ambulancia y luego la visita en el hospital, donde está claro que tiene miedo de un hombre. El DS Masood le dice a Nikki que Shannon ha sido abusada sexualmente y sospecha de Abdul, su padrastro separado. Shannon aparece en casa de Nikki y acepta a regañadientes volver al hospital. Mientras tanto, un grupo de hombres jóvenes asiáticos está atrayendo y explotando a chicas blancas de la escuela para el comercio sexual. Ya tienen a la amiga de Shannon, Amy, y van tras otras dos, Hannah y Lauren. Los patólogos investigan dos casos aparentemente no relacionados: los restos de una niña encontrados en un equipaje de aeropuerto abandonado y un hombre tatuado, John Dear, que murió envenenado. Luego se encuentra un tercer cadáver, el de Amy.

Leo gives evidence at a custody hearing in the wake of a child's death,his opinion over-ruling that of Dr Helen Karamides,which annoys her former pupil Nikki,who sees Helen as the victim of the male establishment and cannot believe the accusation that Helen is retaining tissue samples from past cases. Nikki is also approached by Andy Farmer. His mother Annie was the appropriate adult at the interview with serial killer Arnold Mears,who now directs Annie to the sites of his victims' remains where she collects their bones. Andy wants Nikki to help identify them. Nikki also discovers that Helen had a professional involvement with Mears.

As Leo's replacement Thomas Chamberlain arrives Nikki investigates the murders of Rachel Freedman, shot in the head, and her little autistic son Nathan, who was poisoned. Nikki rejects policewoman Anne Burchett's theory that Rachel killed them both but is perturbed when an impostor, claiming to be Rachel's sister, visits the morgue. At the same time the disfigured corpse of Eva Liron is discovered, killed with the same poison as Nathan. She had been the nanny to French hot shot footballer Isaac Dreyfus and was planning to blackmail him over a sex tape of them both. Jewish Isaac is a controversial figure due to his anti-Muslim sentiments but he denies ant part in the murders. Then another victim, Isaac's agent Mousa, is discovered dead.

Forensic evidence given by Nikki contributes to the release on appeal of disturbed ex-soldier David Bennetto, charged with murdering two gay boys, one of whom he had sex with. DI Rachel Klein is not convinced of David's innocence , especially when a rent boy calling himself Byron Lee is shot dead and David's car is caught on CCTV near the murder scene. The fact that Nikki is dating Bennetto's solicitor Greg Walker makes her partial in the inspector's eyes and she is removed from the case. On the night that yet another gay youngster Charlie Masham is also shot Greg, on a date with Nikki, gets a frantic phone call from Bennetto and they go to his flat where he points a gun at them after he discovers Nikki has found his kitbag containing the murder weapons

La policía rodea el apartamento, pero David le entrega el arma a Greg, explicando que era el arma de su padre, que había encontrado y quería deshacerse de ella. Nikki es verbalmente abusada por el padre de Charlie y el inspector DI Klein quiere suspenderla, pero Clarissa y Jack descubren que el arma encontrada por David no mató a Charlie ni tampoco pudo haber matado a Byron Lee. Los patólogos descubren que el verdadero asesino en serie tenía un inquietante conocimiento del pasado de David Bennetto y su motivo no era sexual, sino obsesionado con tener poder sobre los demás. Las circunstancias también terminan la participación de Nikki con Greg Walker.

El equipo investiga el tiroteo sistemático de una familia que estaba de picnic junto a un río. El caso hace revivir recuerdos de la muerte de una joven junto a ese mismo río hace 10 años.