Officially, the Cold War is over, and the hand of friendship has been exchanged in public. In private, though, the intelligence war continues. A British trawler strays into Russian waters. On its return, the captain has a package for British Intelligence. For the next four years, a high-ranking Russian naval officer provides MI6 with priceless information. But suddenly he goes quiet. Clearly under suspicion, the decision is made to get him out. But his controllers in London know nothing about him.

Only she knows the truth. Only he can tell the world. Vienna, 1946. A brilliant German scientist spirited out of the ruins Nazi Europe in search of a new life. Moscow, 1964. A rising star of the British diplomatic service whose job is not what it seems. London, the present day. A once promising academic offered an opportunity to seal his place in history. Their stories, their lives, and the fate of the world, are bound by a single document: The Scarlet Papers. The devastating secrets contained within teased by a brief invitation: Tomorrow 11AM. Take a cab and pay in cash. Tell no one.

Northern Ireland, spring 1981. Hunger strikes, riots, power cuts, a homophobic serial killer with a penchant for opera, and a young woman’s suicide that may yet turn out to be murder: on the surface, the events are unconnected, but then things—and people—aren’t always what they seem. Detective Sergeant Duffy is the man tasked with trying to get to the bottom of it all. It’s no easy job—especially when it turns out that one of the victims was involved in the IRA but was last seen discussing business with someone from the loyalist Ulster Volunteer Force.

When disgraced spy Solomon Vine's friend and rival Gabriel Wilde vanishes without trace, it's only Vine who might be able to discover what has happened to him. A single missing file holds the key. That, too, is gone. But its contents, Vine is told, are incendiary. There were few Wilde could trust. And being one of them appears to have fatal consequences. But as Vine's off-the-books investigation begins to reveal the shocking truth, he realizes there's much more at stake than one man's life.

Moscow, 1936. In a deconsecrated church, a young woman is found dead, her mutilated body displayed on the altar for all to see. Captain Alexei Dimitrevich Korolev is asked to investigate. But when he discovers that the victim is an American citizen, the NKVD - the most feared organisation in Russia - becomes involved. Soon, Korolev’s every step is under close scrutiny and one false move will mean exile to the frozen camps of the far north. Committed to uncovering the truth, Korolov enters the realm of the Thieves, who run Moscow’s underworld.