At Princeton University, a famed geneticist dies inside a biohazard lab. In Rome, a Vatican archaeologist is found dead in St. Peter's Basilica. In Africa, a U.S. senator's son is slain outside a Red Cross camp. The three murders on three continents bear a horrifying connection: all the victims are marked by a Druidic pagan cross burned into their flesh. The bizarre murders thrust Commander Gray Pierce and Sigma Force into a race against time to solve a riddle going back centuries, to a ghastly crime against humanity hidden within a cryptic medieval codex. Aided by two women from his past,—one his ex-lover, the other his new partner—Gray must piece together the horrifying truth. But the revelations come at a high cost, and to save the future, Gray will have to sacrifice one of the women at his side. That alone might not be enough, as the true path to salvation is revealed in a dark prophecy of doom.The ultimate nightmare is locked within a talisman buried by a dead saint—an ancient artifact known as the Doomsday Key.