When Detective Inspector Jack Lennon tries to track down his former lover Marie McKenna and their daughter, his superiors tell him to back off. But now an assassin stalks Belfast, tying up loose ends for a vengeance-driven old man. As Lennon unravels a conspiracy that links his daughter to a killer named Fegan, the line between friend and enemy blurs.

When single mother Collette McVeigh is arrested for her part in an aborted IRA plot in London, an MI5 officer offers her a choice: lose everything and go to prison or return to Belfast to spy on her own family. With her son's life in her hands, Collette chooses to place her trust in the MI5 and return home. When her brothers' secret operation is ambushed, suspicions of an informant are raised and Collette finds both herself and her family in grave...