When Kremlin intelligence analyst Nestor Blok contacts MI5 to facilitate his defection from Moscow, it seems like the perfect job for Ryan Kerrek, the Discretionary Tactical Unit’s newest asset. Devising a bold strategy with Jørn ‘Bear’ Larsen of the Norwegian Intelligence Service, Kerrek hopes to smuggle the Russian into Great Britain using a daring method not employed since World War II. And yet it soon transpires that others are willing to take extreme measures to capture and interrogate Blok. As unforeseen events unfold in the United States, Kerrek questions whether the enigmatic Blok is all he appears to be, and fears that Russian spymasters have outwitted and out-manoeuvred them all.