The conclusion to this trilogy.
Turns out certain demons have been planning revenge on the human race. They have figured out a way to take over a human host which gets rid of many of the drawbacks of being summoned. Nathanial finally stops being a complete ass right at the end and kills off all the hybrids with Gladstone’s Staff. Finally, he unleashes the complete potential of the Staff to destroy the leader and in the process gives his life up.
I have to admit, at first I didn’t like the ending. Then I realized these books were about Bartimaeus, not Nathanial. Which is why I never really got excited about them. Bartimaeus should have been the sidekick…