"The Locked Tomb" is a science fiction fantasy series by Tamsyn Muir, beginning with the novel "Gideon the Ninth." The story follows Gideon Nav, a necromancer's servant, who is drawn into a deadly competition among the houses of the Nine Houses to serve the Emperor. The series blends elements of mystery, horror, and romance, set in a universe where necromancy and swordplay coexist. The narrative features a diverse cast, including Harrowhark Nonagesimus, a powerful necromancer and Gideon's master. The series explores themes of loyalty, identity, and the complexities of relationships against a backdrop of political intrigue and supernatural elements.