Mainspring is a nonstop adventure yarn that's the equal of anything from Fritz Leiber or Robert Howard, with a premise that's so mindbendingly weird that it'll have you giggling in public. The idea is that the universe is a giant, magnificent clockwork, the planets themselves on gears whose teeth are visible in the night sky. A humble apprentice is catapulted into adventure when an angel charges him with a quest to save the world from ruin when its mainspring winds down.
There's zeppelin battles, demented theology, and lots and lots of clocky, mechanical goodness here. This is blasphemy at its finest.