CIA headquarters in Langley, Virginia, receives a cryptic message from an agent operating deep undercover in Russia: "He has betrayed us and wants to go to war." Unable to make contact, the Director of Operations is forced to turn to one of his most deadly field officers--Will Cochrane. His mission: infiltrate the remote submarine base in eastern Russia, locate the agent operating under the codename Svelte, and decode his message--or die trying.

It's a near-impossible task--even for a man who carries the codename Spartan, a title given to the most effective Western intelligence officers. Will successfully locates the base but finds Svelte near death, his last words a final clue: Only Sentinel can stop him. Now it's up to Will to uncover the true meaning of Svelte's message . . . and discover the identity of the legendary operative known only as "Sentinel." An unforgettable, enthralling espionage thriller, written by a real-life former agent.