From the book:
As Europe entered the 11th century, millennial fever became all too real. On the thousandth anniversary of the death of the Son, evil opened a doorway into the world, and all Hell literally broke loose.
The first seal in the Revelations of St. John has been broken, but not in the way people thought. The dead have risen, but they are hungry for the flesh of the living!
Worse, the Secret Revelations say that there is war in Heaven, and the outcome is not as certain as people tend to think...
Hell is on Earth, and Heaven is silent. Only miracles and acts of faith show that the Divine still smiles on your existence. Otherwise, the fate of humanity is in your hands.
Dark Millennium begins in the historical 11th century, but takes a sharp turn when the quasi-biblical End Times begin. Players will take the role of extraordinary individuals called upon to battle the undead menace, for Church, for King and for simple survival.
Dark Millennium includes character generation, cultural, religious, historical and geopolitical information on the 11th century, three short adventures, and rules for miracles, magic and other manifestations of the supernatural in this alternate historical setting.