A master at combining historical and scientific intrigue with cutting-edge adventure, New York Times bestselling author of Map of Bones and Black Order James Rollins returns with his most relentless, high-octane thriller to date—a terrifying story of an ancient menace reborn to plague the modern world . . . and of an impossible hope that lies hidden in the most shocking place imaginable: within the language of angels.

From the depths of the Indian Ocean, a horrific plague has arisen to devastate humankind—a disease that's unknown, unstoppable . . . and deadly. But it is merely a harbinger of the doom that is to follow.

Aboard a cruise liner transformed into a makeshift hospital, Dr. Lisa Cummings and Monk Kokkalis—operatives of the shadowy covert organization SIGMA Force—search for answers to the bizarre affliction that has inexplicably washed ashore. But there are others with far less altruistic intentions. In a savage and sudden coup, terrorists hijack the vessel, turning a mercy ship into a floating bio-weapons lab.

At a Fourth of July celebration a world away, SIGMA's commander Gray Pierce thwarts the murderous schemes of a beautiful assassin—a would-be killer who holds the first clue to the discovery of a possible cure. With the fate of every man, woman, and child on Earth hanging in the balance, Pierce joins forces with the woman who wanted him dead, and together they embark upon an astonishing quest—one that winds through Venetian tombs, Byzantine cathedrals, and jungle-encrusted ruins—following the trail of the most fabled explorer in history: Marco Polo.

But time is an enemy as a worldwide pandemic grows rapidly out of control. And as a relentless madman dogs their every step, Pierce and his unlikely ally are being pulled into an astonishing mystery buried deep in antiquity and in humanity's genetic code. And as the seconds tick closer to doomsday, Pierce will realize he can truly trust no one—not the bewitching enigma who runs at his side or even those who are closest to him—for any one of them could be . . . a Judas.