Seventeen-year-old Zélie Adebola is a divîner, a person born with latent magical powers, identified by their stark-white hair. Divîners face political, economic, and social discrimination after the Raid, a violent event where King Saran, leader of the kingdom of Orïsha, ordered all maji, practitioners of magic, to be killed. Since then, magic has been extinct in Orïsha. Zélie's mother, a maji, was violently murdered during the Raid; the memory of her death still traumatizes Zélie, her father, and her brother, Tzain. Zélie empowers herself by secretly training under the tutelage of Mama Agba, a divîner, to fight with a staff. On the day of Zélie's graduation from Mama Agba's school, royal guards arrive and demand increased taxes from the divîners. Zélie, driven by a desire for justice, talks back to the guards, who threaten her with physical and sexual violence.
Tzain informs Zélie that their father, whom they call Baba, is in trouble. Ever since his wife's murder, Baba has suffered from blackouts and needs constant care; however, Zélie left her father to go to the graduation ceremony. Zélie and Tzain learn their father endangered himself trying to make money to pay the increased taxes, in order to prevent Zélie from being sent to the stocks, the kingdom's exploitative labor force. Zélie and Tzain decide to sell a rare fish in Lagos to earn enough money to pay the taxes.
After being harassed by guards, Zélie successfully trades the fish for a large sum of money. But as she tries to leave the market, Princess Amari pleads for Zélie's help. Having witnessed the murder of her closest friend, Amari stole a scroll that awakens magic in those who touch it. Zélie fights the guards, and Tzain helps them escape on Zélie's lionaire, Nailah. They head to Zélie and Tzain's village, Ilorin. Having never been allowed out of the palace, Amari is enthralled by the village and the sea. They seek Mama Agba's advice, and she reveals she was a maji who escaped the Raid after she had a vision warning her about the violence to come. After touching the scroll, Mama Agba conjures a vision of Zélie, Tzain, and Amari traveling to the ancient temple of Chândomblé to restore magic.
Suddenly, fire erupts, and Ilorin burns. Prince Inan, Amari's brother, oversees the destruction, as his father has tasked him to bring Amari back to Lagos and prevent magic's return by any means necessary. While the village burns, Zélie, Amari, and Tzain escape by water. Encouraged by Baba and Mama Agba, they head to the temple. Zélie meets Inan in a dream and realizes that he is a Connecter, a maji with the power to influence dreams and minds. Inan grows increasingly obsessed with finding Zélie and killing her, as his magic torments him, and he believes killing Zélie will end magic.
While they stop to get supplies, Tzain and Zélie notice scars on Amari's body. Amari explains that her father forced her and Inan to fight with real swords so they would grow up strong since the king lost his first family to the maji. Amari trades the headdress that her deceased friend, Binta, gave her, for supplies in the city of Sokoto. When Zélie, Amari, and Tzain reach the holy temple, a sêntaro, or protector of magic, named Lekan knocks them unconscious and ties them up, thinking they stole the scroll. However, he realizes they are on a mission to restore magic and explains the history of how the Sky Mother created the gods and humans. He then awakens Zélie's connection to the Sky Mother using blood magic so Zélie can perform a sacred ritual that will restore magic. The ritual weakens Zélie, but her magical abilities grow exponentially. Inan and Kaea arrive on the mountain, and Zélie, Amari, and Tzain barely escape. In the chase, Kaea kills Lekan, and Inan loses his snow leopanaire.
Inan tries to suppress his magic, though it physically pains him to do so. Zélie, Tzain, and Amari reach Ibeji, a desert outpost run by corrupt guards. The laborers in the stocks work long hours and can only afford to drink polluted water. To make matters worse, the Ibeji nobles make laborers fight to the death for entertainment. The prize for this competition, which no one ever wins, is the sunstone, a piece of the Sky Mother's soul that Zélie needs to complete the ritual. Zélie, Tzain, and Amari decide to compete, using Zélie's powers to reanimate dead spirits. They win the sunstone, though Zélie almost dies, and Amari is racked with guilt after she kills a man to save Zélie's life. Inan again sees Zélie in the dreamscape and figures out she is in Ibeji. Kaea sees him using magic and decides to tell King Saran; in a panic, Inan accidentally kills her with his magic. He continues his search for Amari and Zélie alone.
Inan catches Amari, Tzain, and Zélie at Gombe. While Inan and Zélie battle, a group of masked strangers kidnap Tzain and Amari. When Inan touches Zélie, her memories of her mother's death transfer to him. Overcome with sympathy and understanding for the first time, he decides not to kill her and convinces her to team up to find Amari and Tzain. The kidnappers are a group of divîners living in a secret camp. They interrogate Amari, not believing her story about restoring magic with the scroll. Zélie and Inan break into the camp using the sunstone to amplify their powers. They are almost killed by Kwame, a Burner with the power to control fire, until Zu, the young leader of the divîners, stops the battle. Zu decides to help the three with their mission to restore magic after they celebrate the festival of Àjọyo. Zélie teaches Inan to control his magic, and they kiss, sending Tzain into a fury. Angered, Zélie accidentally harms Tzain with her magic and begins to worry that restoring magic is not safe.
Amid celebrations, the Royal Army attacks the divîner camp. Zu and many other divîners are killed, and Zélie is captured and taken to an army camp. King Saran tortures Zélie for the whereabouts of the scroll, breaking her spirit. Amari and Tzain team up with other divîners to infiltrate the king's stronghold and rescue Zélie. Though a maji heals Zélie, she still bears a scar on her back reading "maggot," a slur for maji, and her connection to her magic is severed. With only one day to complete the ritual and restore magic, the divîners decide to cross through Jimeta, a city overrun with mercenaries and criminals. Zélie meets Roën and convinces him to take her to the temple on the island of Zaria, where the ritual must occur. When the mercenaries spot King Saran's warships, they quietly commandeer a warship, sail to the temple, and disguise themselves in guards' uniforms. Zélie confides in Amari that she cannot use magic, and Amari urges her to try the ritual anyway.
They reach the island and find a massive temple where the ritual will take place. However, the group is ambushed by King Saran and Inan, who have taken Baba hostage. Zélie hands over two artifacts in exchange for her father. One of the guards tries to shoot Zélie, but Baba jumps in front of the arrow, sacrificing his life for hers. Zélie's magic returns, and Inan tricks her into destroying the scroll. During the battle, Inan uses magic to save his father's life. Saran realizes Inan was the one who killed Kaea and stabs Inan. Baba's sacrifice works to restore Zélie's power, and she forges a link with her ancestors back to the Sky Mother, which restores magic not only for the divîners but also for some nobles, including Amari.
