A former Empire lies in ruins having been over run by barbarian hordes and the evil magic wielding acolytes that drive them on. This is no mere invasion however as the hordes have all but rooted out the entire religious and magical underpinnings of the old regime. The human strife is just a cover for a war between supernatural beings. A small band of rebel warriors and mages cling to some hope of restoring the Empire but what hope can they have when even their god is thoroughly outmatched.
I believe this was Cobley's first novel but it shows no lack of confidence and is very enjoyable. I did get confused at times because the author crams a lot of characters and their respective plot threads into one novel. Cobley's later Humanities Fire saga was even more confusing in this respect so it looks like this is a trait the author has no intention of outgrowing.