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.

Isaac is arrested but club bosses deny knowledge of the sex tape whilst Rachel's widower Adam tells the police that Eva Liron had been Nathan's nanny but had left suddenly. With Mousa shot by the same gun as Rachel ambitious Inspector Leighton assumes that he was delivering the blackmail hush money and was killed by Isaac, whom he wants to nail, though the pathologists will not assist in any stitch-up. Then Clarissa discovers that Adam and Isaac both donated money to Israel and the motive appears to be that they were targeted by anti-Zionist terrorists after Eva had picked them out. But who is the mystery woman posing as Rachel's sister and who perpetrated the murders? The pathologists assist the police in finding out.

As DCI Butcher moves closer to making an arrest, the team continue to pursue their own lines of inquiry. Amy's past begins to catch up with her and converge with the team's investigation.