John Hughes joined MI5 during the war on terror and was at the forefront of averting the biggest terrorist plots on UK soil. Now in his mid 40s and married with two children he’s struggling to adapt to the new MI5, where threats to national security have changed and he’s forced to adapt to the values of a progressive work environment.

Follow a dysfunctional team of MI5 agents—and their obnoxious boss, the notorious Jackson Lamb—as they navigate the espionage world's smoke and mirrors to defend England from sinister forces.