Set in 2013 Britain after a devastating terror attack on London, this drama from the makers of Spooks follows the lives of young MI5 officers fighting to return the country to normal. Britain in 2013 is a highly monitored world; surveillance spills into everyone's private lives as MI5, the new secret police, defend the realm. Society is tense - watching and being watched all the time. This level of protection comes at the cost of liberty and a new generation of young, newly-trained spies are fighting for everybody's freedom. With more underground working methods, more rogue and immoral officers than today and a deeply competitive attitude - their missions call for a new brand of heroism. But who can they trust?