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 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