After her son almost dies, corrupt detective Lou Slack attempts to make amends for her misdeeds but realises she must betray the dangerous drug baron she has been working for.

Lou struggles to keep up appearances with Col, inviting further suspicion. Desperate to get away from Col and clear her conscience, she seeks help from an unexpected source.

Lou and Vernon's plans to take Col down threaten to trigger a bloody gang war; Owen and Donal grow ever closer; Esther becomes curious about Lou's erratic behaviour.

Lou makes one last desperate attempt to bring Col down, but things do not go exactly as she hoped; feeling powerless, Ceri resorts to drastic action in order to defend his family.

As Vernon is taken into custody, Lou attempts to live a normal life within the law and deal with suspicion from Sandy, but finds herself pushed to breaking point.