Gideon the Ninth by Tamsyn Muir is a dark and thrilling gaslamp fantasy novel. The story takes place in a decaying space empire where necromancers and their sword-wielding cavaliers compete for power. Gideon Nav, a skilled swordswoman, is forced to serve her lifelong nemesis, Harrowhark Nonagesimus, in a deadly trial that could grant them both immortality. With its unique blend of science fiction, fantasy, and gothic horror, Gideon the Ninth is a gripping and atmospheric read that will keep you on the edge of your seat.