January, 1981. Jim Dowd and Maureen O'Brien, special forces soldiers, enter a bitterly divided Belfast on an undercover mission to infiltrate one of the city's most dangerous Catholic neighbourhoods and help change the course of a war that nobody is winning. The Ardoyne is a perilous world, where a hint of their true identities would prove fatal. But it is also full of courage and loyalty. Jim admires this community - and feels guilt at their deception. When they receive shocking orders, Maureen knows they must act swiftly and ruthlessly, but can she rely on Jim? And if they rebel, are they betraying their country; or being betrayed?