Thomas Kell, former MI6 officer, devoted his life to the service, but was left with nothing except grief and a simmering anger against the Kremlin. Then Kell is offered an unexpected chance at revenge and embarks on a mission to recruit a top Russian spy, who is in possession of a terrifying secret... 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?