Set in 2013 Britain, following a devastating terror attack on London, this drama from the makers of Spooks follows the lives of young MI5 officers fighting to return Britain to normality. Britain in 2013 is a highly monitored world, which spills I to everyone's private lives. MI 5, the new secret police, defend the realm. Society is tense - watching and being watched all the time. But this level of protection comes at the cost of liberty, and a new generation of young, trained spies are fighting to regain that liberty. Full of personal hope, they are fighting for everyone's freedom. With more underground working methods, more rogue and immoral officers than today, and deeply competitive - their missions call for a new brand of heroism. But who can they trust?