The year is 1991, and the ancient evil of the Nephilim, long dormant, has awakened. Ashmodiel, centuries-old Patriarch of the Children of Ramiel, has decreed that the time has come to summon their ancestor, the fallen Watcher Ramiel, from the desert realm of Dudaëra, to which he has been exiled. For nurse Liz Grisanti, the terror begins when the Ramielites announce they will kidnap and sacrifice six blond, blue-eyed six-year-old children at a series of rituals between Halloween and the Winter Solstice -- and Liz's younger daughter, Bella, exactly fits the description of the cult's chosen victims. Called in as the Massachusetts State Criminal Investigation Division's specialist on cults, Detective Lieutenant Patrick Michael Pentangeli consults his mentor, occult master Trevor Faulkner, whose contacts in the field include rabbis and priests, as well as medievalist Sebastian Barber - who happens to be dating Liz Grizanti. As a series of angelic children are kidnapped and sacrificed and the days progress inexorably toward the Winter Solstice, the tightly knit circle of friends endeavors to protect Bella from falling victim to the Banim Ramiel - and, ultimately, to stop the final sacrifice before Ramiel can be summoned for from his imprisonment and free the legions of Nephilim to create a Hell on earth.