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.

Nikki y Jack son llamados a una estación de metro donde un exsoldado sin hogar ha caído debajo de las ruedas de un tren subterráneo. Mientras tanto, la recepcionista del hotel de la estación, Lana Sutherland, se encuentra con otro hombre sin hogar, Owen Hanmore, a quien invita a quedarse con ella y se convierte en su amante. Mientras tanto, ocurre una serie de asesinatos sin una conexión visible, más allá del hecho de que todas las víctimas habían utilizado la misma estación de metro.

The team assists DI Paul Renick following the assumed suicide of Jamal Al Sham and discover that he was murdered and was a people smuggler, blamed by Varkey Khoury, head of a family of Syrian refugees, for killing his wife. Varkey's 15 year old daughter Akka approaches Nikki for news of her mother, leading to Nikki sheltering her whilst the police haul in another young woman Tamara as a likely killer. At the refuge camp in Calais apparent altruist Yusuf Hamed assists 12 year old Sosa to come to England whilst Kalil Aziz, an associate of Sham, is also murdered and the police and pathologists make a grim discovery in an English forest.

The investigation continues to take unpredicted turns, with Nikki managing to get behind the mask of the lead suspect.

El CID local encuentra discrepancias dentro de las filas a medida que las pruebas se acumulan contra el oficial de policía acusado.