Hannah and Billy join forces once again to try to uncover the leak at Bristol Police HQ. Dubravka is joined by her nephew Goran and comes under pressure to shift the drugs. Meanwhile, Christian and Bianca find that Costa Rica isn't safe.
Against her will Bianca is reunited with Dubravka and becomes a prisoner in her own home. Christian tries to get back to the UK undetected. Hannah and Billy uncover the mole and strike a deal with him before Dubravka can intervene.
Hannah and Billy begin to suspect they can't trust Kane. When they discover Bianca is back but alone, Hannah fears the worst but Billy reveals a plan to keep him safe. The race is on to get to Christian before the Mimicas can.
Hannah and Billy hunt for the rat that betrayed them and finally make a break-through. This time Kane is prepared to listen. However, the closer they get to finally bringing down the Mimicas, the more danger they find themselves in.
The police close in on the Mimicas and DCI Harris in Bristol. Each fiercely determined to secure a better future for their families, the war between Hannah and Dubravka reaches a bloody conclusion.
