In the wilds of Mongolia, a research satellite has crashed, triggering an explosive search for its valuable cargo: a code-black physics project connected to the study of dark energy--and a shocking image of the Eastern Seaboard of the United States in utter ruin.

At the Vatican, a package arrives containing two strange artifacts: a skull scrawled with ancient Aramaic and a tome bound in human skin. DNA evidence reveals that both came from the long-dead Mongol king Genghis Khan. Commander Gray Pierce and Sigma set out to discover a truth tied to the fall of the Roman Empire, to a mystery going back to the birth of Christianity, and to a weapon hidden for centuries that holds the fate of humanity.