When her married lover and fellow police officer Sean Hardacre goes missing, Detective Inspector Hannah Laing launches an urgent manhunt.

Hannah and her new partner Billy start investigating the Mimica family. But a shocking discovery makes Hannah want to pull the plug on the entire operation.

Stefan discovers that Christian has been meeting with Hannah. Will Christian be forced to take drastic action to protect himself?

Traumatised by what he's done, and hopelessly tangled up in the undercover investigation, Christian takes a trip with Davor that will reveal everything that he needs to know.

With Christian out of action, Hannah and Billy are at a loss - and it begins to look like the Mimicas will get away with their crime.

In a dramatic final showdown, the undercover police team attempt to bust the Mimicas' drug smuggling operation. But they're in for an unpleasant surprise.

DI Hannah Laing and crime boss Dubravka Mimica will both stop at nothing to protect their estranged sons. Hannah tries to identify the source of a leak from within the police force, while Dubravka comes under pressure from the family in Zagreb to shift drugs. Meanwhile, Christian and Bianca find that their Costa Rican hideout isn't as safe as it seems

Bianca is reunited with her mother Dubravka against her will, and quickly becomes a prisoner in her own home. Christian tries to evade the Mimicas and get back to the UK undetected to save her. Hannah and Billy have uncovered the mole and struck a deal with him to reveal all before Dubravka can intervene

Hannah and Billy become suspicious of Chief Superintendent Kane and the pair fear for Christian when Bianca returns alone

Hannah and Billy finally make a breakthrough in the case while they're searching for the rat that betrayed them but the closer the get to bringing down the Mimicas, the more danger they find themselves in

The police are closing in on the Mimicas and Nicky Harris in Bristol, and with all parties fiercely determined to secure a better future for their families, the war between Hannah and Dubravka reaches a bloody conclusion