Thomas Blades, a 17th century curate, discovers a magical door to another world - or rather to an alternative Earth. But here, humanity is not the top of the food chain, as Blades finds when the poor, burrow-dwelling humans he stumbles over are hunted and eaten by the Null - mighty, ravening beasts whose intelligence and killing ability makes them top predator.

Returning to our own world for weapons, Blades vows to become humanity's saviour on his new earth and, over the years, builds an empire of which he becomes the first God-king. Power shifts between humanity and Null but as the humans grow in sophistication, so comes treachery, jealousy and murder - and God-king Blades will change much from the timid cleric who first happened upon his domain...