Summary
Gideon the Ninth is a 2019 science fantasy novel marking the debut of New Zealand author Tamsyn Muir. This genre-defying tale blends elements of gothic horror and space opera with contemporary humor and queer representation. Set in a distant future where necromancers rule nine planets, the story follows the irreverent Gideon Nav and her nemesis Harrowhark Nonagesimus as they navigate deadly trials to become immortal servants of the Emperor. Named as one of the best books of 2019 by NPR, Vox, and the New York Public Library, Gideon the Ninth won the 2020 Locus Award for Best First Novel and was shortlisted for the prestigious Nebula, Hugo, and World Fantasy Awards. It also launched her bestselling Locked Tomb series. With its memorable characters, intricate world-building, and inventive blend of comedy and horror, the novel has secured Muir’s place as a rising star in the science fantasy world.
Plot
Gideon Nav, an indentured servant of the Ninth House, attempts to escape her life of servitude but is thwarted by Harrowhark Nonagesimus, the house's heir. Despite their mutual dislike, Harrow recruits Gideon as her cavalier for a series of trials set by the Emperor. The trials, held at Canaan House on the First House's planet, will determine which heirs become Lyctors—immortal necromancers serving the Emperor.
At Canaan House, Gideon and Harrow join heirs and cavaliers from other Houses in exploring the mansion and solving necromantic puzzles. As suspicious deaths occur, alliances form and tensions rise among the participants. Gideon and Harrow's relationship evolves from antagonism to reluctant cooperation as they make progress in the trials, uncovering hidden chambers and ancient experiments.
Eventually, the true nature of Lyctorhood is revealed—a necromancer must consume their cavalier's soul to achieve immortality. This discovery leads to further conflict, deaths among the Houses, and another revelation. One participant, Dulcinea of the Seventh House, is actually an imposter—Cytherea the First, a rogue Lyctor with a vendetta against the Emperor.
In the final confrontation with Cytherea, Gideon sacrifices herself to save Harrow, forcing her to become a Lyctor. Harrow defeats Cytherea but loses consciousness. She awakens on the Emperor's ship, learning that Gideon's soul is now irreversibly merged with hers. As one of only two survivors, Harrow agrees to serve the Emperor as Harrowhark the First, in exchange for restoring the declining Ninth House to glory.
Themes
Power dynamics and politics in an isolated, hierarchical society
The complex relationship between duty and personal desires
Identity and self-discovery in a restrictive environment
The blending of science fiction and fantasy elements
Dark humor as a coping mechanism in grim circumstances
Trust and betrayal in high-stakes competitions
The nature of sacrifice and its consequences
Setting
Gideon the Ninth takes place in a star system called Dominicus, ruled by an immortal Emperor who is worshipped as a god. The system consists of nine planets, each home to a great House that practices its own school of necromancy. This interplanetary empire has existed for 10,000 years, blending advanced technology with arcane magic.
Much of the story unfolds at Canaan House, a decaying mansion on the planet of the First House. This sprawling, labyrinthine structure serves as the backdrop for the Emperor's trials, where heirs from each House compete to become Lyctors—immortal necromancers who serve as the Emperor's elite warriors. Canaan House is filled with hidden chambers, ancient artifacts, and deadly secrets that the characters must navigate.
The Ninth House, home to protagonists Gideon and Harrowhark, is described as a gloomy death cult tasked with guarding a mysterious Locked Tomb. This isolated, ossifying society stands in stark contrast to the other Houses and the wider galactic civilization, including the Emperor's armies known as the Cohort. The juxtaposition of these various settings—from crumbling necropolises to high-tech spaceships—creates a unique blend of science fiction and gothic horror.
Characters
Gideon Nav: The protagonist. An orphan raised in the Ninth House, Gideon is a skilled swordswoman with a sarcastic attitude. She reluctantly becomes Harrowhark's cavalier and travels to Canaan House for the Lyctor trials. Throughout the story, Gideon's relationship with Harrow evolves from antagonism to friendship and loyalty.
Harrowhark Nonagesimus: The Reverend Daughter and heir of the Ninth House. A powerful necromancer, Harrow is driven by the desire to save her dying house. She has a complex history with Gideon and struggles with guilt over the circumstances of her birth. Harrow's journey involves uncovering the secrets of Lyctorhood and confronting her own vulnerabilities.
Ianthe Tridentarius: The heir of the Third House. Ambitious and ruthless, Ianthe becomes the first of the new generation to achieve Lyctorhood by consuming her twin sister's soul. Her actions reveal the dark nature of Lyctorhood and set her apart as a potential antagonist.
Palamedes Sextus: The heir of the Sixth House. A brilliant scholar and detective, Palamedes works closely with his cavalier Camilla to unravel the mysteries of Canaan House. He forms an alliance with Gideon and Harrow, contributing significantly to their investigations.
Dulcinea Septimus: The heir of the Seventh House. Initially presented as a terminally ill, charming character who captures Gideon's interest, Dulcinea is later revealed to be an impersonation by Cytherea the First.
Cytherea the First: A rogue Lyctor posing as Dulcinea Septimus. The primary antagonist, Cytherea orchestrates many of the deaths at Canaan House as part of her revenge plot against the Emperor.
Camilla Hect: The cavalier of the Sixth House. A skilled fighter and loyal companion to Palamedes Sextus, Camilla plays a supporting role in the investigations and battles at Canaan House.
Silas Octakiseron: The heir of the Eighth House. A devout and stern character who adheres strictly to religious principle, Silas adds to the tension and conflict among the Houses.
Quick facts
Gideon the Ninth is Tamsyn Muir's debut novel, published in 2019.
The book is the first in The Locked Tomb series, followed by Harrow the Ninth and Nona the Ninth.
Gideon the Ninth features lesbian necromancers in space, a unique premise that garnered significant attention.
The novel blends elements of science fiction, fantasy, horror, and humor.
Muir consulted with HEMA martial artist Lissa Harris for realistic depictions of sword fighting.
The audiobook is narrated by British actress Moira Quirk.
Gideon the Ninth won the 2020 Locus Award for Best First Novel and was shortlisted for the Nebula, Hugo, and World Fantasy Awards.
Amazon's editors named it the best science fiction and fantasy book of 2019.
NPR included Gideon the Ninth in its list of the 50 best sci-fi/fantasy books of the 2010s.
Gideon the Ninth is the first book in Tamsen Muir’s Locked Tomb series, followed by Harrow the Ninth (2020) and Nona the Ninth (2022).
About the Author
Tamsyn Muir (1985-) is a New Zealand author and rising star in the world of speculative fiction and science fantasy. Her debut novel, Gideon the Ninth, won the 2020 Locus Award for Best First Novel and was a finalist for the prestigious Nebula, Hugo, and World Fantasy Awards. The first adventure in her bestselling Locked Tomb series, it was followed by Harrow the Ninth (2020) and Nona the Ninth (2022).
Known for its intricate world-building, complex characters, and genre-defying innovations, her work is also informed by her sharp sense of humor and her perspective as a lesbian. In addition to her novels, Muir has published a fantasy novella titled Princess Floralinda and the Forty-Flight Tower and several short stories, receiving nominations for the Nebula Award, Shirley Jackson Award, World Fantasy Award, and Eugie Foster Memorial Award.
Born in Australia, Muir grew up in New Zealand. A graduate of the Clarion Science Fiction and Fantasy Writers’ Workshop, she also holds a degree in education. She currently lives in Oxford, England, and is working on future projects, including a cyberpunk western trilogy.
