Agent Will Cochrane is back.  Fourteen days ago CIA headquarters in Langley, Virginia received a cryptic message from an agent operating deep undercover in Russia. The message read, “Whatever happens, do not go to war. Repeat, do not go to war.”  Unable to make contact, they decide to send in their most deadly field officer—special agent Will Cochrane. Will’s task is simple: infiltrate the secret submarine base in eastern Russia’s Avacha Bay, locate the agent operating under the codename ‘Svelte’, and decode his message or die trying.  But after successfully penetrating the base, Will finds Svelte gasping for his very life after a knife attack, his final words barely audible. Now Will must find out what they mean and who could possibly be the ’Sentinel.’