The Hundred Thousand Kingdoms, the first book of the Inheritance Trilogy, is set in a world ruled by the Arameri family, who derive their absolute power from the god Bright Itempas. Long ago, three gods existed: Itempas (god of light and order), Nahadoth (god of darkness and chaos), and Enefa (goddess of twilight, life, and death). Itempas murdered Enefa and enslaved Nahadoth along with three godlings, giving them to his most devoted follower, Shahar Arameri, as weapons. Since then, the Arameri have used these captive gods, called the Enefadeh, to impose their rule over the world.
Yeine Darr, a nineteen-year-old chieftain of Darr, a small northern kingdom, is the daughter of Kinneth, an Arameri heiress who abdicated to marry Yeine's commoner father, bringing the family's wrath upon Darr. One month after Kinneth dies mysteriously in her sleep, Yeine's grandfather Dekarta Arameri summons her to Sky, where the Arameri palace floats on a thin column above the city. He names Yeine a third heir alongside his niece Scimina and nephew Relad Arameri, shocking the court. The losers will likely die. T'vril, the palace steward and a halfblood relative, orients Yeine and urges her to receive a blood sigil, a magical forehead mark confirming identity and rank, from Viraine, the palace scrivener, before sunset.
En route, Yeine encounters Scimina with Nahadoth, the enslaved Nightlord, held by a silver collar. Scimina deliberately releases him, and he transforms into something monstrous, pursuing Yeine through the palace. Sieh, the Trickster god and one of the Enefadeh, rescues her through hidden passages. When Nahadoth finds them in a state of madness, Yeine stabs him, clearing his frenzy. Zhakkarn, Nahadoth's daughter and the goddess of battle, then appears. The Enefadeh secretly alter Yeine's sigil so its loyalty-compelling magic will not affect her, then send her to Viraine for the visible mark. Yeine reveals her suspicion that Kinneth was murdered: She found a puncture wound on Kinneth's forehead where her sigil scar had been.
Yeine works to build alliances and investigate her mother's death. She attends the Nobles' Consortium, the empire's governing assembly, and uses her authority over assigned subject nations to resume trade with Darr, reversing her homeland's economic isolation. Relad refuses an alliance, warning only that Scimina attacks whatever her enemies love most. Nahadoth, whose nature shifts with the time of day, with madness overtaking him at dawn and dusk, visits Yeine at night in a calm state. He reveals that the official account of the Gods' War is false: Itempas killed Enefa not because she attacked him, but because the Three quarreled over Nahadoth and Itempas could not bear to share him.
In Kinneth's preserved apartment, Yeine finds a hidden pendant shaped like a fruitstone, the symbol of Enefa. In the palace library, she discovers hidden artwork of all three gods, including an image of Enefa whose face closely resembles her own. The discovery triggers a violent vision, and Kurue, the godling of wisdom, reveals the truth: The Enefadeh placed Enefa's damaged soul into Yeine before her birth. During a three-day fever, Yeine experiences Enefa's story as a fairy tale about three divine siblings who created life, including the first godling child, Sieh, before the family tore itself apart.
When Yeine recovers, Sieh explains what happened. Kinneth came to the Enefadeh to save Yeine's father from the Walking Death, a magical plague. They cured him; in exchange, Kinneth agreed to let them place Enefa's soul in her unborn child. The soul, trapped in the mortal realm by the Stone of Earth, a remnant of Enefa's physical form, needs a living vessel to heal. If Yeine wields the Stone at the succession ceremony, she can free the Enefadeh, but the act will kill her. The ritual requires a designated sacrifice to transfer power to the chosen heir. Yeine was brought to Sky not to win but to die. Because the soul is too fragile and bonded to Yeine's body to be forcibly removed, the Enefadeh need her cooperation. Yeine agrees to the plan but insists on her own terms: a genuine chance to win.
Ras Onchi, a High North representative in the Nobles' Consortium, warns Yeine that Scimina has sponsored a war petition targeting Darr. Yeine travels to Darr with Nahadoth, and her grandmother confirms that the neighboring kingdom of Menchey is arming for invasion. Yeine threatens Menchey's minister with Nahadoth's power, but Scimina discovers the interference and retaliates by torturing Sieh and Nahadoth in the palace arena. Yeine confesses to stop the torture, and Scimina announces she will resume the attack on Darr.
In her remaining days, Yeine uncovers more truths. Nahadoth reveals that Dekarta killed his own wife, Ygreth, at his succession ceremony 40 years earlier, as tradition required, and that Kinneth devoted herself to revenge upon discovering this. He also reveals that Viraine sent the Walking Death to Darr, hoping to kill Yeine's father so Kinneth would return to Sky. Yeine suspects Viraine killed her mother as well. Relad secretly offers to deploy mercenaries against Menchey if Yeine names him heir. She agrees. On the eve of the ceremony, Yeine gives herself to Nahadoth, who carries her beyond the universe and brings her back alive, the first mortal to survive such an encounter in centuries.
At the dawn ceremony atop Sky's central spire, Dekarta confesses he did not kill Kinneth; he brought Yeine to Sky because he suspected she had murdered her own mother. Yeine names Relad as heir, but as she reaches for the Stone, Viraine whispers, "I'm sorry" (367), and stabs her through the back.
In death, Yeine's soul watches the conspiracies unravel. Kurue confesses that she killed Kinneth and betrayed the Enefadeh's plan to Itempas, preferring the god's mercy over trusting a mortal. Nahadoth reveals that Viraine is the mortal vessel of Itempas himself, who has hidden in human form for 20 years. Itempas manifests in an eruption of light, destroying Viraine, and offers Nahadoth freedom if he returns. Nahadoth refuses, and the gods' battle shatters the chamber. Scimina kills Relad during the chaos, while Sieh and Zhakkarn fight Kurue.
Between death and life, Enefa's soul tells Yeine she can be reborn: not as Enefa, but as something new, a goddess carrying Enefa's power while remaining herself. Enefa must merge fully with Yeine to make the return possible. The Stone enters her body, and Yeine is reborn with divine senses, growing a colossal World Tree around Sky. Together with the freed Nahadoth, she sentences Itempas to walk the earth as a powerless mortal until he learns to love. She kills Kurue, sends Zhakkarn to protect Darr, and designates T'vril as the new Arameri heir. Sieh, who as Enefa's firstborn has longed for his mother's return, asks if Yeine is his mother. She says no but takes his hand, and together with Nahadoth, they pass beyond the mortal realm.