An ancient artefact, backed up by a prophecy that's as vague as it is irritating, unearths itself in the hopes of being accidentally put together and getting a good, old-fashioned apocalypse going. It's up to Ezechias, an earnest angel undergoing Authority training, to hunt it down and destroy it before the whole world blows to bits. Well, that, or it's up to Rook, an insouciant demon with business cards more stylish than he actually warrants, to hunt down the angel and use any means necessary to ensure his failure. Either way, the apocalypse may be nigh, with Rook and Ezechias at the centre of it all, and if they get a little distracted by each other... well, humankind's had a good run, hasn't it?