Zélie and Tzain bury their father, Baba, at sea. Zélie struggles to use her magic during the ritual—she experiences flashbacks of the day Baba died, when Zélie inadvertently brought magic back to Orïsha not just for maji like her, but for some nobles now known as tîtáns. Zélie and Tzain, with the help of the mercenary Roën, plan to install their co-conspirator Amari, a tîtán and the runaway princess, on the throne with her mother Queen Nehanda’s blessing. Amari announces her rule when she learns that Nehanda is probably dead due to an attack on the capital city, Lagos, by a maji resistance group known as the Iyika. During Amari’s announcement, however, Nehanda arrives, calls for Amari’s death, and reveals that she’s a wildly powerful tîtán—she almost brings a domed building crashing down on Amari and her group. Roën leaves when Amari can’t pay him for his help, and Zélie screeches that they have to leave the country. She mounts her lionaire, Nailah, and gallops away, but flies off into a tree.
Zélie wakes in a dreamscape belonging to Inan, Amari’s brother whom they believed was dead. Inan’s betrayal is the reason Baba died, so Zélie conjures black roots that choke Inan. Inan wakes up in the palace at Lagos and discovers that the monarchy is at war with the Iyika, but that Nehanda is ruling as queen and Ojore, Inan’s adoptive cousin, is at the palace. A few days later, Inan prepares to take the throne, wearing the robes of his violent and cruel father, King Saran, whom Amari killed. Ojore is openly upset that Inan is a tîtán—before the Raid, Ojore’s parents were murdered by Burner maji. Inan takes his throne, fiddles with the bronze coin that Zélie gave him, and commands the monarchy to create rations for everyone. When Ojore catches a maji girl named Raifa stealing, Inan declares that any Iyika who defect will get double rations.
Zélie wakes up in the real world and tells Amari that Inan is alive—and that she intends to kill him. Zélie, Amari, and Tzain prepare to free captured maji from a fort, but Roën appears on behalf of the Iyika, which hired him to fetch Zélie. Zélie and the others meet the Iyika a few days later and Zélie learns that her childhood mentor, Mama Agba, started the group. Mama Agba leads Zélie’s group to a sanctuary called the Ile Ijosin. Zélie meets the elders of the other clans. The Tamer elder, Na’imah, has a note from Raifa about Inan’s offer of rations. Zélie insists that Inan is a liar and when Amari tries to speak up in support of her brother, the Connector elder, Ramaya, spits that as a tîtán and a princess, Amari is unwelcome. A few days later, Raifa burns the food in Lagos. To retaliate, Inan and Ojore sneak out of Lagos to find the Iyika hideout. Burners ambush them, but Inan’s magic bursts out, breaking his arm but saving his and Ojore’s lives.
Amari begs Zélie to teach her to use her magic. Their session doesn’t go well; Amari’s ashê burns her. Zélie explains that when a maji channels their ashê using Yoruba spells it’s like removing a tiny bit of a dam; but when tîtáns use magic, it’s like taking away the entire dam. Amari asks to learn Yoruba, but Zélie insists that Yoruba is sacred to the maji. Zélie eventually relents. The next day, Mama Agba holds the ceremony in which Zélie ascends as the elder of the Reaper clan. The prior elder—a teen boy named Mâzeli—steps down to become Zélie’s Second. During Zélie’s ìsípayá—a god-granted vision—the god Oya shows her different ribbons of light twisting together. During the celebration, the Iyika get news of what Inan did to Raifa’s outpost. Amari offers to contact Inan, but Ramaya threatens Amari. Amari challenges Ramaya to be the Connector elder. As they battle, Amari loses control and puts Ramaya in a coma. Amari stays in her room for days, while Healers refuse to heal her bruises. Zélie visits Amari before an elder meeting and explains to her that magic isn’t about power; it’s the reason why the monarchy tries to kill maji, and it’s not something tîtáns can just learn.
Amari agrees to attend the elder meeting, but the other elders are rude and don’t want to listen. Zélie agrees with the other elders that they can’t trust Inan, so suggests that they journey to the Chândomblé temple and retrieve scrolls containing spells. The elders set out immediately. Inan, Nehanda, and General Jokôye are initially concerned that the Iyika are heading for Lagos, but Inan realizes that Chândomblé is their target and takes a force there. The Seer elder, Dakarai, realizes this, and Amari crafts a plan to tunnel into the temple. Though they make it into the temple, soldiers, including Inan, chase them, and they battle General Jokôye before Zélie discovers the incantation that allows them to enter the room with the scrolls and seal it. Amari insists that once they gather scrolls, they must burn the rest. Amari touches Zélie and the two suddenly rise into the air. A ribbon of navy light comes from Amari’s chest. When they return to the ground, Zélie realizes what happened: Amari—and Nehanda—are what Zélie terms cênters, or tîtáns who can draw power from other tîtáns of the same clan. This, she believes, is what Oya showed her in her ìsípayá, and this is how they can beat Nehanda. The Iyika fight their way out of the temple, though Zélie almost kills Inan. After the Iyika are gone, Nehanda destroys Chândomblé. Later, Mama Agba explains that Zélie activated the moonstone, which is power given by the gods. It allows people to do things like join their lifeforces or create cênters, but it requires a sacrifice—which, she suggests, Saran’s death at Amari’s hand was; his death made Amari and Nehanda cênters. Amari wants to speak to Inan, but Zélie and the other elders forbid it.
On the first morning of training, Mama Agba visits Zélie. Zélie feels unworthy to lead her clan after putting Mâzeli in danger at Chândomblé, but Mama Agba reassures her. Zélie asks if it’s possible to use the moonstone to combine different types of magic, but Mama Agba says it yields disastrous results: previously joined maji created poisonous majacite. Zélie leads her three Reapers, Mâzeli, Bimpe, and Màri, in summoning shadows. At the end of the day, Amari goes to Zélie for help translating the incantation for creating a dreamscape. Zélie destroys the scroll when she realizes Amari wants to use it to talk to Inan, spitting that Inan only does the right thing when it’s easy and will betray them every other time. Mama Agba comforts Amari and insists that she has to understand that both Zélie and Inan are merely the most recent fighters in a centuries-long war. She also reminds Amari that as a cênter, Amari doesn’t need incantations.
Inan struggles to stay awake for a council meeting and to talk to Ojore, who’s incensed that Inan couldn’t kill Zélie and Amari at Chândomblé. Inan falls asleep and wakes up in Amari’s dreamscape. Inan offers to bring a treaty to the Iyika. The next day, while Zélie is out practicing with her Reapers, she sees Amari sneaking away. When she follows Amari, she discovers Inan. Though Zélie is incensed, she can see that the treaty is a good thing. Before she can agree to anything, they hear horns: Inan’s armies are coming. Amari thinks that Zélie was right to not trust Inan, so she uses her abilities as a cênter to draw on his ashê and begins to attack the soldiers. Zélie and Mâzeli fight bravely, but General Jokôye, a Winder and a cênter, mounts a terrifying attack. Zélie and Mâzeli use the moonstone and connect. It allows them to win, but Mâzeli dies from the strain and Zélie only survives because Mama Agba breaks the connection. Amari beliefs she ruined everything, while Inan thinks that the Iyika have to die.
Three days later, Zélie panics every time she tries to wash off Mâzeli’s blood. Roën lets himself in, helps her breathe and clean up, and shares new intelligence. Zélie races to the elder meeting going on downstairs to share the news: Inan and his forces are splitting up between Lagos and the village of Ibadan, so they have an opening to escape Orïsha. Amari insists they have to fight instead, while Inan is an easy target in Ibadan and Lagos is mostly undefended. The elders agree with Amari and throw a celebratory party. Zélie tries to join in, but instead she and Roën dive and take a ride on a whale. Back at Zélie’s quarters, she asks Roën to stay, but she panics when they start to remove each other’s clothing. She insults him so she can protect her breaking heart and he leaves.
Zélie decides to join the elders in going to Ibadan while the other forces head for Lagos. She joins the Tider elder Nâo and Roën as they dive in underground caves, hoping to infiltrate the valley. However, Roën, angry at Zélie, shouts that she should stop playing the victim and barges ahead, setting off bombs that collapse the cave. As Zélie drowns, Mama, Baba, and Mâzeli show her that the monarchy planted the bombs. Suddenly intent on living, Zélie frees herself and then finds Roën. He’s close to death and trapped, so Zélie severs his stuck arm and tows him to the surface. As Roën dies, Zélie sees a flicker of gold and remembers her ìsípayá. She believes that Oya showed her Roën and so calls on the moonstone to bind her lifeforce to Roën’s.
Meanwhile, in Ibadan, Nehanda admits to Inan that she’s the reason that the Raid happened: she dissolved peace talks between maji and the monarchy by setting Burners on nobles. Inan is horrified, especially when he discovers that Ojore heard Nehanda’s confession. Ojore reveals that he’s a tîtán and tries to kill Inan, but Nehanda kills him first. They escape when the bombs go off, but Amari doesn’t know this and has a plan to sacrifice the villagers of Ibadan to kill Inan and Nehanda. She and two maji, Jahi and Imani, unleash a tornado of cancer on Ibadan that hits as Zélie and Roën stumble into the village. Zélie saves as many people as she can in the well. When the clouds clear, Amari and Zélie see the monarchy’s note: they have the other Iyika fighters in Lagos. The elders imprison Amari and Healers try to save Zélie and Roën. As Tzain and two other elders, Kâmarū and Khani, agree to join their life forces with Zélie, Zélie knows that this is what Oya showed her: that they can use the moonstone to come all the elders’ lifeforces. Zélie and Khani, a Healer, are able to bring the dead villagers back to life.
Roën fires his mercenary crew and insists he’s coming with Zélie. Later, Zélie goes to Amari’s cell and explains what they’re going to do with the moonstone. Amari realizes that they need a sacrifice and offers herself, but Zélie refuses. Mama Agba steps in and says that she’ll be the sacrifice—she knows now that in her ìsípayá, she saw herself acting as such. Zélie and the elders perform the ceremony and their hearts beat as one. The elders sail to Lagos and pass Zélie and Tzain’s burnt former village, Ilorin, but they see that Zélie’s home has been rebuilt. Zélie finds that Inan rebuilt it and left her letters there, along with the bronze coin she gave him. He explains that he’s dissolving the monarchy.
In Lagos, Inan sneaks a sedative into Nehanda’s drink. As he begins to speak to the room of nobles, they hear explosions outside. Zélie and the elders combine their powers to destroy the monarchy’s army and defenses. They quickly infiltrate the palace. Amari runs into Nehanda and though Nehanda insults her, Amari declares that she can choose to be a better queen. The elders find the captured Iyika in the cellars, and Inan finds Zélie. Zélie begins to draw the lifeforce out of Inan and kill him, but Roën races at her with a breathing mask, a moving cloud of white behind him. Roën and Zélie collapse when the cloud hits them and Zélie wakes some time later, chained in a ship at sea.
