In this space fantasy novel, people belong to one of the nine Houses, which are spread out across nine different planets. The Emperor alone resides in the First House, and orders the Second through Ninth houses to send their necromancer and cavalier (the necromancer's bodyguard/swordsman) to his planet.
The Ninth House sends Harrowhark and Gideon, life-long enemies, who must work together to bring glory to the Ninth House and receive the power of immortality.
The book starts off quite slow as the author introduces Gideon and Harrow and do a bit of world-building. It's all a bit hard to get your head around what's happening but the book picks up pace once all the necromancers and their cavaliers land on the Emperor's planet.
Necromancy is spooky in general but the Ninth House takes it to the next level with skull face paint and a reputation for being super-religious. It's amusing to watch them try and interact with the more “normal” necromancers of the other Houses in comparison.
It's disappointing that Harrow and Gideon build up relationships with all the other Houses, and then they all die. Even the relationship between Gideon and Harrow, too. It makes me less interested in reading the second book. Also their deaths didn't really feel that emotionally impactful either. Maybe there wasn't enough time to properly build up that relationship between the characters.