The Obelisk Gate

Schaffa, Essun's former Guardian, awakens underwater after Essun's devastating counterattack during the climax of The Fifth Season. He is about to drown when, out of desperation, he allows the entity (manifested as a force of pure rage) that powers his and the other Guardians' abilities to take control of his body for a brief period. Though he is saved from death, the resulting brain damage leaves him with profound memory loss, and he is unable to fully recall his past as a Guardian. He is rescued by a family of fishermen on the coast. His unfamiliarity with his own supernatural abilities leads him to inadvertently kill them all, and he sets out south in response to a vague half-remembered memory.

The story resumes soon after Nassun's father discovers her brother is an orogene. In a blind rage, and deducing Nassun is likely an orogene as well, he beats Nassun's brother to death and abducts her as he flees Tirimo, their hometown. He intends to take Nassun south, where he has heard of a group of Guardians that can "cure" Nassun of orogeny.

Nassun has always been close to her father, due largely to her strict and unforgiving relationship with her mother Essun, who has been secretly teaching her to hone her orogenic abilities in order to avoid detection. Nevertheless, she fears her father, who now is aware she is an orogene as well. Her father strikes her early in the journey, and is immediately overcome with guilt; Nassun, however, learns to harden her heart against him, and stops viewing him as her true father at all.

They move south through much hardship, and witness firsthand the devastation wrought by Alabaster's fracturing of the entire continent further north. The Fifth Season triggered by this event steadily worsens as they travel. Finally, they reach the promised settlement: a town called Found Moon, administered by a group of Guardians, though not affiliated with the Fulcrum. The town is led by Schaffa, who has used it to shelter young orogenes during the years since he arrived.

Nassun and her father settle in Found Moon, and Nassun begins to rapidly advance through the ranks of the makeshift Fulcrum the Guardians have established. She forms a particularly strong bond with Schaffa, who is fiercely protective of her and becomes her father figure in lieu of her biological father. She begins to understand that orogeny, in contrast to the teachings of her mother and the Guardians, is not just about moving heat energy from one place to another; she learns to perceive a mysterious silver energy, generated by living things, that underpins all of her orogenic powers. Her abilities increase to the point where she begins to learn to draw power from one of the obelisks floating nearby, much as her mother had many years earlier. Her use of this power causes her to accidentally kill one of her classmates by turning him to stone while suffering a nightmare.

As Nassun grows in her abilities, her father starts to realize she is not being "cured" of her "sickness". He confronts Schaffa and later attempts to kill Nassun. She reluctantly uses her powers to turn her father to stone as well.

Essun remains in Castrima, a comm that lives in a huge underground geode. Ykka, the comm's leader, is an orogene herself, and due to her influence, orogenes are permitted to live openly alongside others. The comm is sustained by many mysterious functions of the geode that appear to operate by magic, such as air recyclers and climate control, though the inhabitants do not understand the underlying mechanisms; however, they do note that the mechanisms only function when orogenes are present.

Also present in Castrima is Alabaster, Essun's former lover and an immensely powerful Fulcrum orogene. Alabaster is dying, his body slowly turning to stone as a consequence of using the energy of the obelisks to break the entire continent in half and trigger the current Fifth Season. He is watched over by a stone eater he has named Antimony, who appears to have an adversarial relationship with the mysterious "child" Hoa, now revealed to be a stone eater himself, who accompanied Essun as she fled Tirimo.

Alabaster begins imparting some of his knowledge to Essun concerning the obelisks and the nature of orogeny. As revealed at the end of The Fifth Season, the Moon has not been seen for at least several thousand years prior to the events of the book, and most are not aware it ever existed. Alabaster states that his fracturing of the continent was a method to generate enough raw geological heat and power to allow a sufficiently powerful orogene to use the obelisks to recapture the Moon and end the Fifth Seasons (its highly elliptical orbit is one of the reasons for the geologic instability of the Stillness). Alabaster is also aware of the silver energy Nassun discovered, which he identifies as magic, the true fundamental force that makes orogeny (and the mechanisms of Castrima) possible. He struggles to teach Essun to use it effectively as his condition deteriorates, all the while reconciling with Essun over the death of their child years ago. He finally dies, his body turning completely to stone, after expending the last of his strength to rescue Essun from an attempt to harness the power of one of the nearby obelisks.

Throughout, tensions within the society of Castrima are revealed, as the coexistence of orogenes and normal people within the community is uneasy at best. These issues are exacerbated by the appearance of a raiding party from a rival comm, Rennanis, who have left their home further north and intend to take Castrima by force. Initially unable to win in an outright attack, they besiege the comm by locating the ventilation shafts for the geode, intending to force them out into the open.

Having no choice, the inhabitants of Castrima prepare for battle. Rennanis' offensive is aided by their own faction of stone eaters, who are opposed to Alabaster and Antimony's plans. Facing the loss of her new home, Essun successfully uses Alabaster's training to repeat his accomplishment, tapping the power of all the obelisks worldwide to form the Obelisk Gate. She uses the immense power of the Gate to turn every inhabitant of Rennanis to stone simultaneously.

Castrima is saved, but the mechanisms of the geode have been irreparably damaged by the assault, and the comm faces starvation and suffocation if they remain. They begin preparations to set out into the worsening Fifth Season to find a new home.

The Obelisk Gate won the Hugo Award for Best Novel in 2017.[9][10][11][12][13] It was the second award for Jemisin's Broken Earth series (after The Fifth Season in 2016), making Jemisin the first author in over two decades to win the Best Novel Hugo in two consecutive years.[14] Moreover, The Obelisk Gate's victory came as part of a women-heavy slate of winners at the 2017 Hugos, which included best novel, novella, novelette, and short story.[9][10][15]

Outside of the Hugos, The Obelisk Gate was nominated for the Nebula Award for Best Novel, but lost to Charlie Jane Anders' All the Birds in the Sky.[16][17] It won RT Book Reviews' 2016 award for best high fantasy novel.[18]