The young Martin McGartland makes a living as a street hustler in the 1980s in Belfast when the IRA tries to recruit him. He does not accept their methods and is then recruited by the british police to work as an undercover spy inside the IRA. He is able to give information about terrorist attacks to the police, but when the IRA uncovers him he is being dropped by the police. He can only survive by jumping out of a window and then has to escape. He first flees to Scotland but as he still doesn't feel safe he leaves his family behind and escapes to Canada. Still, the IRA finds him and shoots him, though he survives.