From the back of the book:
A game of war, myth and horror.
The ultimate conflict has begun. An ancient force is reborn, and a war to determine the destiny of humankind must be fought by forces Mundane and Celestial. Angels walk on Earth once again, and the Old Gods have returned.
From the ravaged cities of war-torn Europe to the slums of future-day America, Human and Immortal alike must fight an old and deadly enemy.
Armageddon is a complete role-playing game, with rules to create Gifted, Mundane and Supernatural characters, an overview of a near future world wracked by war and occult forces, and the Unisystem, a set of game rules that can use dice, cards or be completely story-driven to fit the needs of your gaming group.