Nat, a 47 year-old veteran of Britain's Secret Intelligence Service, believes his years as an agent runner are over. He is back in London with his wife, the long-suffering Prue. But with the growing threat from Moscow Centre, the office has one more job for him. Nat is to take over The Haven, a defunct substation of London General with a rag-tag band of spies. The only bright light on the team is young Florence, who has her eye on Russia Department and a Ukrainian oligarch with a finger in the Russia pie. Nat is not only a spy, he is a passionate badminton player. His regular Monday evening opponent is half his age: the introspective and solitary Ed. Ed hates Brexit, hates Trump and hates his job at some soulless media agency. And it is Ed, of all unlikely people, who will take Prue, Florence and Nat himself down the path of political anger that will ensnare them all.