When her married lover and fellow police officer Sean Hardacre goes missing under mysterious circumstances, Detective Inspector Hannah Laing persuades her colleagues to launch an urgent manhunt. She manages to contact one of Sean’s confidential sources, but can “Issy” help her discover Sean’s whereabouts before it’s too late?

Hannah and her new partner, Billy Murdoch, start investigating the Mimica family, who they believe are responsible for Sean’s murder. They discover the Mimicas are planning to smuggle a massive quantity of cocaine into the country, but when Hannah discovers the identity of Sean’s contact “Issy”, she immediately wants to pull the plug on the investigation.

Stefan discovers Christian has been meeting with Hannah and he tells Davor that Christian is supplying information about the Mimica family’s criminal activities to the police. Christian has a carefully prepared cover story, but will it convince Davor? Or will he be forced to take more drastic action to preserve his cover and protect himself?

Davor tells Bianca that Stefan has gone to Croatia, but she works out what has really happened to him and makes a proposal to Christian. Traumatized by what he’s done and hopelessly tangled up in the undercover police investigation, Christian opts instead to take a trip with Davor that will reveal everything he needs to know about Operation Krajina.

Hannah and Billy work out how the Mimicas plan to smuggle the cocaine into the UK, but with Christian out of action they have no way of knowing when or where the consignment will be delivered. When another drug dealer confesses to Sean’s murder, it looks like the Mimicas will get away with it, until Bianca makes a discovery that turns everything upside down.

The undercover police team attempt to bust the Mimicas’ drug smuggling operation, but they are in for an unpleasant surprise. With Billy and Christian’s help, Hannah manages to turn the tables on the Mimicas and set up a dramatic and conclusive showdown.