The film is based on the original novel of former film reporter Tom Brady. The story begins in 1973 when a little girl named Crockett was killed because she made a mistake in escorting her younger brother. 20 years later, the adult Clotter (Andrea Resborough Andrea Riseborough) becomes a very radical IRA for revenge and joins two brothers, Gerry and Cornell, to take over a tricky task arranged by the organization-to create a shocking explosion on the London Underground. But in this operation, Cloter is intercepted by Mike (cliff Owen Clive Owen), a senior official of MI5, who gives him two options: one is to go to prison for 25 years and never to see his son again; the other is to betray his brother and become a top secret informant of MI5. To this end, Cloter had to betray his family and his beliefs as an IRA. But in a series of actions, both sides found a mole, so Cloth bore the brunt of the victim.