Thomas Kelk thought he was done with spying. A former MI6 officer, he devoted his life to the Service, but all it has left him with is grief and a simmering anger against the Kremlin.
Then Kell is offered an unexpected chance at revenge. Taking the law into his own hands, he embarks on a mission to recruit the Russian spy he blames for the murder of his girlfriend.
Kell tracks his nemesis from Kiev to London, but soon finds himself in a high-stakes game of cat and mouse in which it becomes increasingly difficult to know who is playing whom.
As the mission reaches boiling point, the threat of a catastrophic terrorist attack looms over Britain. Kell is faced with an impossible choice. Loyalty to MI6 - or to his own conscience?