An expedition off the Italian coast reclaims a World War II-era German midget submarine. When the two-man sub is opened, it contains a single corpse, and an artifact from Adolf Hitler's bunker that was thought to be lost to history. On Long Island, an elderly man and woman are brutally murdered. FBI Agent Link Johnsten is called in to assist local authorities and to maintain the victims' secret. When six unsent letters are discovered in their home, one piques his interest. It's addressed to his friend, CIA Agent Samuel Tolen. Chinese-American physicist, Dr. Sing Liao, is abducted after making an astonishing, yet terrifying, scientific breakthrough.

The intersecting lives of Dr. Liao, a rogue FBI agent, and a billionaire shipping magnate collide. With ties to Nazi Germany, Tolen and Johnsten are swept up in a frantic chase to uncover Adolf Hitler's darkest secret. At stake is the life of an 11-year-old savant-and the possible end of the world.