At a tracking station in Virginia, U.S. Navy officers watch in horror as one of their communications satellites plummets into the Indian Ocean and panic spreads through the British and American intelligence services.

When a Russian intelligence officer approaches MI5 with vital information about the cyber sabotage, he refuses to talk to anyone but Liz Carlyle. But who is he, and how is he connected to Liz?

Is this a Russian plot to disable the West's defenses? Or is the threat coming from elsewhere? As Liz and her team search for a mole inside the Ministry of Defense, the trail takes them from Geneva, to Marseilles, and to Korea in a race against time to stop the Cold War from heating up.