The Book in Brief
Gideon Nav has made eighty-six failed attempts to escape the Ninth House. On her eighty-seventh, Harrowhark Nonagesimus defeats her with bone constructs and forces a bargain. The Emperor Undying has summoned each House's necromantic heir and cavalier to Canaan House, where one pair may attain Lyctorhood. Harrow's designated cavalier, Ortus Nigenad, has fled with his mother, so Gideon agrees to take his place in exchange for eventual freedom. She trains with the rapier and accompanies Harrow to the First House.
At Canaan House, the heirs meet Teacher and the other House pairs. They receive keyrings and are told to explore without opening locked doors carelessly. Harrow initially abandons Gideon and investigates alone. After Gideon finds her injured inside a bone cocoon, they agree to cooperate. The underground laboratories contain trials that require necromancer and cavalier to combine abilities. Their first victory earns a key and reveals research into the process that created the Emperor's immortal Lyctors.
Magnus and Abigail of the Fifth House are found dead. Judith Deuteros of the Second wants to summon the Cohort, but Teacher prevents anyone from leaving. More keys are discovered, stolen, or hidden. Harrow and Gideon complete the avulsion trial by having Harrow siphon Gideon's life while working at a distance. The trial nearly kills Gideon and shows how naturally the Lyctoral research converts trust into exploitation.
The deaths continue. Human remains appear in an incinerator. Protesilaus, Dulcinea Septimus's cavalier, vanishes. Isaac and Jeannemary of the Fourth are attacked in the facility; a giant regenerating bone construct kills Isaac, and Jeannemary is later murdered. Palamedes determines that foreign bone fragments and altered bodies are part of the crimes. Gideon learns that the Eighth House knows details about her origin and about the destruction of the shuttle that might have carried her away.
Gideon finds Protesilaus's severed head in Harrow's wardrobe. Harrow explains that the man had been dead and reanimated before reaching Canaan House. In the pool, she confesses the Ninth House's foundational crime: her parents killed two hundred children to generate enough thanergy to conceive a necromantic heir. Gideon was the only child who survived. Harrow also admits she opened the Locked Tomb and saw a chained, sleeping girl. Gideon reveals how her childhood accusation led to the suicide of Harrow's parents. They forgive without pretending the past can be repaired and pledge themselves to each other.
The survivors discover that Teacher is a composite revenant made from many souls and that Canaan House was built around the original Lyctor experiments. Ianthe Tridentarius solves the process, kills and consumes her cavalier Naberius, and becomes a Lyctor. Her twin Corona is exposed as a non-necromancer who has spent her life sharing Ianthe's status. Silas siphons Colum during the ensuing conflict; Colum is possessed, kills Silas, and is killed by Ianthe.
Palamedes confronts Dulcinea and identifies her as Cytherea the First, an ancient Lyctor who murdered the real Dulcinea and Protesilaus before the voyage. Dying of cancer and enraged by the Emperor's plans, Cytherea has killed the heirs to stop the creation of new Lyctors. Palamedes accelerates her cancer and detonates himself, but she survives. Camilla, Gideon, Harrow, and Ianthe fight Cytherea and her bone construct as Canaan House collapses.
Realizing everyone will die, Gideon throws herself onto metal spikes. Harrow absorbs her soul and becomes a Lyctor. With Gideon's sword skill and presence inside her, Harrow destroys the construct and kills Cytherea. Harrow later wakes aboard the Emperor's ship. Gideon's body is missing, as are Camilla, Judith, and Corona. The Emperor says Gideon cannot be restored in the way Harrow wants. Harrow accepts service as one of his Lyctors while insisting that he remember Gideon Nav.
Important Characters
Gideon Nav: Orphaned ward of the Ninth House and reluctant cavalier. Her humor, sword skill, anger, and capacity for devotion form the novel's point of view.
Harrowhark Nonagesimus: Reverend Daughter and necromantic heir of the Ninth. She is a bone adept created through the sacrificed energy of two hundred children and is obsessed with protecting the Locked Tomb.
Palamedes Sextus: Heir of the Sixth House, a brilliant psychometric necromancer and investigator. His intelligence is matched by unusual ethical seriousness.
Camilla Hect: Palamedes's cavalier, exceptionally disciplined and dangerous with paired blades. She and Palamedes possess the healthiest partnership among the competitors.
Dulcinea Septimus / Cytherea the First: The apparent sickly heir of the Seventh is actually an ancient Lyctor in disguise. She conducts the murders to prevent the Emperor from creating replacements.
Ianthe Tridentarius: Flesh magician of the Third House. She solves the Lyctoral theorem and deliberately consumes Naberius to gain immortality.
Coronabeth Tridentarius: Ianthe's charismatic twin, presented as a necromancer although she has no necromantic ability.
Naberius Tern: Cavalier to the Third House twins. His cultivated skill and vanity do not protect him from being treated as Ianthe's resource.
Magnus Quinn and Abigail Pent: The warm-hearted Fifth House pair. Abigail's spiritual expertise brings her close to the secret beneath Canaan House before both are murdered.
Isaac Tettares and Jeannemary Chatur: The adolescent Fourth House pair. Their deaths expose the human cost of sending children into an imperial succession trial.
Silas Octakiseron and Colum Asht: Eighth House necromancer and cavalier. Silas's soul-siphoning discipline treats Colum as a conduit and leaves him vulnerable to possession.
Judith Deuteros and Marta Dyas: Second House pair devoted to Cohort law and military authority. Their demand for formal procedure repeatedly clashes with Teacher's rules.
Teacher: Cheerful First House priest who is secretly a composite of many souls connected to the original experiments.
The Emperor Undying: Necromancer Divine and ruler of the Nine Houses. He offers Lyctorhood as sacred service while concealing its origin and cost.
Aiglamene: The Ninth House's elderly swordmaster. Her training prepares Gideon for Canaan House and her reluctant care gives Gideon one of her few stable adult relationships.
> Spoiler Warning: The summaries below reveal all murders, the > secret of Harrow's birth, the Lyctoral process, Gideon's death, and > the epilogue. The standard edition contains 37 numbered chapters in > five acts, followed by an epilogue.
Act One — Chapters 1–9
Act One — Chapter 1. Gideon prepares her eighty-seventh escape from the Ninth House with a shuttle ticket, sword, and pornography. Crux tries to stop her, and Aiglamene arrives to confirm that Harrow will not permit the departure.
Chapter 2. Harrow ambushes Gideon with skeletons grown from bones buried beneath the landing field. Gideon fights fiercely but loses. Harrow invokes an old bargain and takes control of the shuttle plan.
Chapter 3. The Ninth gathers to answer a summons from the Emperor. Gideon sees Harrow's dead parents propped up and controlled as if alive. Ortus and his mother have escaped in the shuttle, leaving the House without a cavalier.
Chapter 4. Harrow and Aiglamene propose that Gideon serve as the Ninth cavalier. Gideon agrees only after extracting a promise of freedom and a military commission once the Lyctor trial is complete.
Chapter 5. A second Imperial letter clarifies that the necromancer and cavalier must travel together to the First House. Harrow worries about the Ninth's poverty, reputation, and inability to present Gideon as a properly trained cavalier.
Chapter 6. For three months Aiglamene retrains Gideon from longsword to rapier, offhand, and formal dueling. Gideon and Harrow leave their dying House. Harrow's tears reveal an attachment to it that her severity usually conceals.
Chapter 7. The Ninth pair arrives at Canaan House and meets the competitors from the other Houses. Gideon is immediately distracted by Coronabeth, Ianthe, and the apparently delicate Dulcinea Septimus.
Chapter 8. Teacher explains that the heirs must rediscover the method of Lyctorhood through the building's locked laboratories. He distributes keys, warns against opening doors without understanding them, and refuses to provide a conventional lesson.
Act Two — Chapter 9. Harrow disappears with notes and keys, ordering Gideon to remain silent and uninvolved. Gideon wanders the palace, meets Magnus and the young Fourth House pair, and begins forming connections Harrow did not authorize.
Act Two — Chapters 10–19
Chapter 10. The Eighth House treats Gideon with unexplained hostility. She meets Dulcinea and Protesilaus more closely and becomes infatuated with Dulcinea, whose vulnerability appears to invite the protection Gideon wants to give.
Chapter 11. The cavaliers spar and display their different styles. Gideon defeats Magnus and evaluates the field, while conversations establish that Canaan House is not simply a school but a grave built over something deliberately forgotten.
Chapter 12. When Harrow remains missing, Gideon accepts help from Palamedes and Camilla. They find Harrow injured in the facility, sealed inside a protective shell of bone after an investigation went wrong.
Chapter 13. Harrow admits that the lower complex contains puzzles and lethal trials tied to locked studies. Gideon refuses to remain a decorative servant and forces Harrow to accept a genuine working partnership.
Chapter 14. Gideon battles a regenerating bone construct while Harrow watches through their coordinated senses and analyzes its governing theorem. The trial demonstrates that cavalier skill is being treated as necromantic data.
Chapter 15. Magnus and Abigail host a dinner celebrating their anniversary. The gathering briefly becomes communal, but rivalries, Dulcinea's illness, and Palamedes's attention to her show how much each pair is concealing.
Chapter 16. Harrow and Gideon defeat the construct and recover a red key. Their triumph ends when they find Magnus and Abigail dead, apparently after falling from a height but bearing signs that the scene has been arranged.
Act Three — Chapter 17. Abigail's spirit cannot be summoned cleanly. Silas uses Colum as a soul siphon, causing pain and instability throughout the room. Teacher warns that the house is becoming more dangerous and still refuses evacuation.
Chapter 18. The Fifth House bodies are preserved. Judith insists that Cohort authority must be contacted, but Teacher forbids access to the shuttle. The heirs reveal more of their keys and suspicions while Harrow opens another study.
Chapter 19. Inside the red-key room, Gideon and Harrow study records of the original Lyctors and a theorem for transferring power between two people. Gideon finds a message containing her own name; Harrow promises greater honesty.
Act Three — Chapters 20–29
Chapter 20. The pair undertakes the avulsion trial. Harrow drains Gideon's life at a distance to power a necromantic task, bringing her close to death. Dulcinea comforts Gideon afterward, while Harrow's fear emerges through uncharacteristic tenderness.
Chapter 21. Camilla examines Gideon's injuries and the Sixth shares information. The group discovers that keys and research have been hidden, exchanged, or stolen, turning the trial into an investigation of the competitors themselves.
Chapter 22. The Fourth House discovers human remains connected to an incinerator, and Protesilaus is missing. Dulcinea collapses. The possibility that an unknown person has been inside Canaan House becomes harder to dismiss.
Chapter 23. Two old bodies are found in the incinerator. Silas holds keys taken from Dulcinea. Judith challenges the Sixth House's authority; Marta fights Camilla and loses, proving how formidable the seemingly quiet Sixth cavalier is.
Chapter 24. Naberius attempts to continue the challenge against the Sixth, but the Ninth and Fourth intervene. Temporary alliances form around the keys and the Lyctoral theorem. Gideon joins Isaac and Jeannemary in searching the lower facility.
Chapter 25. The regenerating bone monster attacks. Isaac is killed, and Gideon drags Jeannemary toward the avulsion room. Gideon is incapacitated; when she wakes, Jeannemary has been murdered and displayed.
Act Four — Chapter 26. The survivors recover the Fourth House bodies. Gideon grieves with Dulcinea and reflects on the cavalier vow of "one flesh, one end." Silas reveals knowledge of Gideon Nav, Ortus, and his mother Glaurica.
Chapter 27. The Sixth and Ninth openly collaborate, using their complementary abilities to examine a key and its door. Harrow forbids Gideon from seeing Dulcinea, and the resulting fight exposes jealousy, fear, and their inability to name their dependence.
Chapter 28. At Eighth House tea, Silas explains that Glaurica's ghost implicated the Ninth in the shuttle explosion and recalls the death of two hundred Ninth children. He demands Harrow's keys, but Colum enforces the promise of safe conduct.
Chapter 29. Gideon spars with Coronabeth until Naberius stops them. In Harrow's room she discovers Protesilaus's severed head, proof that the silent cavalier was never the living man he appeared to be.
Act Four — Chapters 30–37
Chapter 30. Gideon alerts the Sixth and recounts the childhood accusation that led to the deaths of Harrow's parents. Harrow explains that Protesilaus was already a corpse when he arrived. Palamedes observes that a less scrupulous Harrow could already have become a Lyctor.
Chapter 31. In the pool, Harrow confesses that her parents killed two hundred children to create the thanergy needed for her conception; Gideon alone survived. Harrow also admits opening the Locked Tomb and seeing a chained sleeping girl. Gideon and Harrow apologize, forgive what can be forgiven, and make a binding promise to each other.
Chapter 32. The Sixth and Ninth reproduce a key from Palamedes's molecular memory. Teacher is exposed as a revenant composite of many souls, and the house's skeleton servants begin collapsing. An attack leaves Teacher and the priests destroyed, Marta dead, and Judith gravely wounded. An emergency signal calls the Emperor.
Chapter 33. The survivors discover that Abigail's corpse was opened to retrieve a hidden key. Evidence suggests Silas hoarded keys but did not commit the murders. Cremated remains include only part of Protesilaus and tissue from another victim.
Chapter 34. Ianthe announces that she solved Lyctorhood by killing Naberius and consuming his soul. Coronabeth is exposed as a non-necromancer. Silas attempts to oppose Ianthe by siphoning Colum; the emptied cavalier is possessed, kills Silas, and is then killed by Ianthe.
Chapter 35. Palamedes confronts Dulcinea and identifies her as Cytherea the First. She murdered the real Dulcinea and Protesilaus before the trial, then killed competitors to stop new Lyctors from being created. Palamedes accelerates her cancer and detonates himself, but Cytherea survives and pursues Gideon.
Chapter 36. Camilla, Gideon, and Harrow fight Cytherea and the giant bone construct. Ianthe intervenes but loses an arm. Harrow traps the construct and saves Gideon from a fatal fall, exhausting herself. As Canaan House collapses and every defensive plan fails, Gideon realizes the others cannot survive while Harrow remains an incomplete necromancer. She throws herself onto iron spikes, choosing death as the final component of Lyctorhood.
Act Five — Chapter 37. Gideon's consciousness and sword skill continue inside Harrow. Their combined abilities destroy the construct and exploit the damage Palamedes inflicted on Cytherea. Harrow kills the ancient Lyctor, then pulls Gideon's body from the spikes and confronts the fact that victory has made their promised "one end" literal.
Epilogue. Harrow wakes aboard the Emperor's vessel and meets the man worshiped as God. Ianthe is alive, while Camilla, Judith, Coronabeth, and Gideon's body are missing. Harrow asks for Gideon to be restored, but the Emperor says the soul cannot simply be separated from what Harrow has become. Harrow accepts the role of Lyctor and asks him to remember Gideon's name.
Ending Explained
Lyctorhood is not a promotion granted by divine favor. It is a process in which a necromancer kills a cavalier, absorbs the cavalier's soul, and gains continuous access to that person's physical instincts and energy. Ianthe performs the process deliberately and treats Naberius as material. Gideon makes the same mechanism possible through voluntary sacrifice, but consent does not make the institution that demands sacrifice harmless.
Cytherea is both murderer and evidence. She kills innocent heirs, including children, yet her revolt comes from direct knowledge of what the Emperor's immortal order costs. She infiltrates the trial to prevent replacements for a dying generation of Lyctors. The survivors defeat her without disproving her accusation.
Gideon's missing body prevents her death from closing the story. Harrow contains Gideon's soul, but the Emperor's explanation is cautious and incomplete. Camilla, Judith, and Corona are also missing, suggesting another group reached Canaan House before Imperial recovery. The epilogue turns the apparent solution into a larger mystery: who removed the bodies, what does the Emperor know, and why did Cytherea recognize Gideon's eyes?
Harrow's demand that God remember Gideon is an act against institutional erasure. The Empire calls consumed cavaliers necessary components of sainthood. Harrow insists that the person inside her power remains a person with a name. Whether she can preserve Gideon without surrendering Lyctorhood is the central problem carried into Harrow the Ninth.
Unresolved Questions
Why did Gideon survive the massacre that created Harrow?
Who were Gideon's parents, and why did Cytherea recognize something in her eyes?
Who removed Gideon's body, Camilla, Judith, and Coronabeth from Canaan House?
Can Gideon's soul be separated from Harrow without destroying either of them?
What exactly lies in the Locked Tomb, and why does Harrow feel bound to the sleeping girl?
Did the Emperor deliberately conceal the true Lyctoral process?
Why did the original Lyctors accept the sacrifice of their cavaliers?
What did Palamedes learn before his death, and did any part of him survive?
What will Ianthe do with her new power and her dependence on Naberius's absorbed soul?
Was Cytherea acting alone, or does the Emperor face a wider rebellion among his surviving Lyctors?
About the Book
Tor.com Publishing published Gideon the Ninth in 2019. It is Tamsyn Muir's debut novel and the first book in The Locked Tomb series, followed by Harrow the Ninth and Nona the Ninth, with Alecto the Ninth announced as the concluding volume.
The novel was nominated for the Hugo, Nebula, and World Fantasy Awards and won the Locus Award for Best First Novel. This article follows the standard English-language structure: five acts, 37 numbered chapters, and an epilogue.