War hurtles towards us. Not just any war, but nuclear annihilation. Clio Strong, head of British intelligence, has her own doomsday tripwire: a Russian agent in the heart of the Kremlin. Clio?s niece, Aphi, is a lieutenant on board HMS Scimitar, a nuclear ballistic missile submarine lurking in the depths of the North Atlantic, ready to retaliate. Will either survive? Will we?