Episode 1

Drama series set in 2013. After London has been evacuated following a nuclear bomb and the country's power base has shifted north, six new MI5 recruits take up the challenge of gathering intelligence in the fightback.

Charlie Green's first mission with Field Office 19 is to foil an apparent assassination plot against the British prime minister. Charlie finds himself in uncharted territory when he unwittingly becomes team leader and is given five and half hours to track down the would-be killer.