From the Game's Introduction:
Welcome to Angel/Demon: The Rapture. A public domain supplement to the Storyteller system. After being inspired by the professional quality of the public domain supplement Highlander for the same system, I decided to modify a game I had developed for my own Reflex system Angel/Demon to the Storyteller format. Thus we have Angel/Demon: The Rapture. I hope in doing this I have make a useful addition to the World of Darkness, that can be enjoyed by all roleplayers. For I believe this game will add a new dimension to any World of Darkness game that you might be playing. Be it Vampire, Werewolf, Mage, etc.
What exactly is Angel/Demon: The Rapture. and how does it interface with the rest of the World of Darkness? Well, Angel/Demon chronicles the battle that exists between the first born of god, Angels, and the minions of Lucifer, Demons. Or as they know themselves: The Cherubim and the Belial. The mythology surrounding these beings is probably known to most of you, being of Judo-Christian backgrounds, and no matter what your feelings about their true existence we must all understand that in the World of Darkness they are very, very real.
These are the final days. The end of the world is near, and soon all of virtue will be taken up in the Rapture. But Satan's power has grown strong, and his minions, the Belial, move upon the surface of Eden. Corrupting, twisting, defiling. But taking physical forms of their own, these beasts must take the bodies of humans if they are to continue their evil works. Possessing the body, suppressing the mind, corrupting all those around it. Leaping from body to body they continue their destruction, bring more and more mortals one step closer to eternal damnation. But this evil does not go unchecked, for God also has his agents working amongst his children. These creatures, The Cherubim, move through humanity by the same method as their enemy. From body to body, person to person. There mission, though, is not the anti-thesis of the Belial. They are not sent to earth to save humanity, that is not within their power. They are upon the surface of Eden in a desperate holding action against the Belial. They are buying time until the Judgment day. Facing and defeating the Belial where every they encounter them. It is to this desperate battle for time that the two sides raise their forces. Will the Cherubim drive back the Belial and allow the final days to came, or will the Belial swallow up the souls of all the mortals and leave no one to be taken up in the Rapture? Only the players of Angel/Demon: The Rapture. will know for sure.