Slade looks at the kneeling Malina with contempt, wanting revenge for her and her husband’s cruelty toward Auren. As he threatens to kill Malina, he is attacked by a shadow-wielding Dommik. Slade easily captures Dommik and begins to kill him with his rot magic. Malina begs Slade to spare Dommik and her people, offering her own life instead and thanking him for saving the survivors. Surprised by her sincerity, Slade releases Dommik. He then reveals that more Oreans are trapped in Highbell castle, having hung signs pleading for help from the windows. Malina begs for his assistance, and he agrees, stating he will do it only because Auren would have wanted him to. Slade first clears the fae from Highbell castle, then flies to the fae army, where he unleashes his rot magic and summons a dragon-like creature made of smoke to decimate their forces, creating a chasm that cuts off their path into Orea. He reflects that, for Auren’s sake, he must be both a villain and a hero.

The narrative returns to Malina’s perspective. Dommik uses his shadow magic to transport the remaining survivors to Highbell castle. The courtyard is littered with the corpses of the fae Slade killed with his rot magic. Malina is terrified by his power and reflects on her own failures as queen. When Slade returns, he demands she show him “her cage.” Malina realizes with dread that he is referring to the gilded prison where King Midas kept Auren for years and that his hatred for her is rooted in his devotion to Auren. She leads him to the opulent cage on the top floor. Slade silently inspects the room, his fury palpable. Overcome with shame and terror, Malina apologizes, fully expecting him to kill her. Instead, Slade turns and leaves without a word. Left alone, Malina looks at the cage and whispers an apology to the absent Auren.

Leaving Auren’s room, Malina discovers Mist, the late King Midas’s pregnant consort, delirious in the servant’s quarters. Mist lies in a blood-soaked bed and recounts giving birth alone to a stillborn son, whose body was then taken by fae soldiers. Stricken with guilt for her past hatred of Mist, Malina comforts her until she peacefully passes away. Malina arranges for the body to be cared for and for a search to begin for the infant’s remains. She then confronts Slade as he prepares to leave, begging him to take her people to his kingdom for safety. He refuses, revealing he is going to the fae realm to find Auren and warning that no place in Orea is safe as long as the bridge exists. Realizing she’s responsible for the bridge, Malina demands to go with him to blockade the bridge and stop more fae from crossing. Dommik protests but ultimately insists on accompanying her. Slade agrees, giving them one hour to find their own transport.

In a dark prison cell, Auren tries to activate her newly discovered rot magic. She has only vague, manipulated memories and feels things crawling in her mind, a result of Una’s influence. Auren has kept the molded crumbs of a piece of bread as proof that her rot power is real. Focusing on her anger, she successfully summons the rot and decays a piece of fruit. Auren plucks a physical strand of rot from her own hand and inserts it into her ear. The magic travels into her brain and destroys one of the magical “worms” infesting her mind. The creature’s death releases a flood of lost memories: her capture alongside companions named Emonie and Wick; the symbol of a rebellion known as the Vulmin Dyrūnia; and the name Lyāri. Though exhausted, she resolves to destroy every remaining worm and reclaim her mind.

Malina and Dommik fly on a timberwing, following Slade to the ruins of Cauval Castle, where the Bridge of Lemuria begins. The area is heavily occupied by a fae army. Ignoring Dommik’s suggestion for reconnaissance, Slade dives toward the encampment and single-handedly annihilates all the soldiers with his rot magic. Malina and Dommik join him at the bridge’s entrance, a dirt path suspended in a void of thick fog. Slade commands Argo to return to Fourth Kingdom for its own safety. After a sad farewell, Slade steps onto the bridge alone and disappears into the mist.

Slade walks through the disorienting fog of the bridge, where his magic feels suppressed. When he emerges in the fae realm of Annwyn, his power returns, but he finds the land blighted and dead. Following smoke to a military encampment, he confronts a group of Stone Swords, soldiers who serve Carrick. Before a fight can erupt, another group of fae, the Vulmin Dyrūnia resistance, ambushes and kills the soldiers. Hare, who appears to lead the group, describes their opposition to King Carrick’s tyranny, shows Slade the group’s symbol of a broken-winged bird, and explains that Vulmin Dyrūnia means “dawn’s bird” in the fae language. When Slade asks about Auren, they recognize her as the Lyāri Ulvēre, the long-lost heir to the Turley throne, who they say has been captured by the king. Enraged, Slade reveals he is fate-bonded to Auren. The Vulmin identify him as The Rot and his father as the feared figure known as “The Breaker.” Intimidated, the Vulmin agree to lead him to the capital.

In her cell, Auren confronts Una. When Una tries to use her memory-altering magic again, Auren’s power erupts, and her forgotten golden ribbons burst from her back. She uses them to capture and kill Una. Realizing Una’s death doesn’t break the spell on her mind, Auren uses her ribbons to shatter the magic-dampening shackle on her ankle. With her full power restored, she creates a suit of golden armor for herself and kills the guard who comes to the door. Retrieving a Vulmin ring Emonie had given her, Auren steps out of the cell, determined to escape and find her friends.

Auren moves through the vast, multi-level dungeon, using her gold magic to pick the locks on every cell. She frees numerous prisoners while searching for her companions, Emonie and Wick, but cannot find them. She easily defeats the guards who try to stop her. Among the freed are a group of Oreans who recognize her as their leader. A fae prisoner guides them out of the dungeon through a hidden cave behind a waterfall. They emerge onto a plateau overlooking the capital city, Lydia, and the beautiful Glassworth Palace. The other escapees flee into the forest, warning that the city is dangerous. However, Auren hears cheering and feels a strong intuition telling her to go toward Lydia. She instructs the Oreans to hide while she investigates alone.

Commander Ryatt stands with his lieutenants, Lu and Osrik, and a small force of soldiers at the Fourth Kingdom outpost of Cliffhelm. They watch a massive fae army advance across the border from Fifth Kingdom. Knowing they are hopelessly outnumbered, Ryatt prepares to execute a desperate plan that relies on his knowledge of the local terrain. A soldier named Tyde, who has magical sight, provides a detailed report on the enemy’s armor and vulnerabilities. Ryatt rallies his troops, vowing they will stand their ground for all of Orea. He then departs with Lu and a small contingent of riders on timberwings to spring their trap.

Ryatt’s plan is to unleash decades of Slade’s rot magic, which has accumulated in the frozen soil of the borderlands. He sends two soldiers with specific powers—Finley, who can generate heat, and Maston, who can create tremors—to a precise location. Ryatt and his riders then use Roland’s magic to create decoys. Roland tears his shadow into dozens of figures that mimic his movements and lures the fae army onto the weakened ground. Finley melts the ice containing the rot, and Maston’s tremors cause the earth to rupture. Massive, rot-filled chasms open up, swallowing a huge portion of the fae army. During the battle, Ryatt sees that Finley and Maston have been stranded and killed. As he attempts a rescue, his own timberwing, Kitt, is shot and killed, sending him and Tyde crashing to the ground.

From the walls of Cliffhelm, Osrik watches Ryatt’s plan unfold. As the ground collapses on the fae, unexpected allies arrive: Red Raid pirates and a force of timberwing riders led by Queen Kaila, the ruler of Third Kingdom. Just as victory seems certain, the fissures spread to Cliffhelm itself, causing the fortress to crumble. Osrik orders a retreat, but several soldiers die in the collapse. He frantically searches the barracks for Rissa but does not find her there, then races back out and finds her running toward him from the direction of the stables. He carries her to safety, and after a tense argument born of fear, they reconcile. The battle concludes, and a captured fae warns that their “Stone King” will not be stopped. Kaila declares her intention to return to Third Kingdom, but her brother Manu convinces her to ally with Ryatt to plan Orea’s defense.

Slade and his Vulmin guides leave the dead lands and enter the lush, living part of Annwyn. As they approach the capital city of Lydia and the magnificent Glassworth Palace, Slade declares his intent to simply walk to the gates and kill everyone until he finds Auren. The Vulmin are stunned by his blunt strategy. Their debate is interrupted when they see a massive crowd flocking into the city. Suddenly, Slade sees a beacon of golden light, which he recognizes as Auren’s unique aura, shining from within Lydia. The bond between them surges, confirming her location. He immediately abandons his plan to attack the palace and rushes toward the city to find her.

Auren steals a cloak and slips into the bustling city of Lydia. She follows the crowd to an outdoor arena where a satirical play is being performed. The play crudely mocks the Turley family and the Vulmin resistance, portraying them as greedy and foolish traitors. Auren recognizes it as propaganda and notices several unamused Vulmin supporters in the audience. After the performance, King Carrick appears and takes a throne overlooking the stage. He presents a golden-skinned woman who looks exactly like Auren but is really Emonie.

King Carrick forces Emonie to bow, claiming that she’s not the rightful heir or the leader of the rebellion and has sworn allegiance to him. Wick and other Vulmin prisoners are then brought out to be publicly whipped and executed, with the gold figure being forced to administer the first blow. Carrick uses his stone magic to control Emonie’s movements by manipulating the stone cuffs around her wrists. As Emonie is forced to raise a whip to strike Wick, Auren’s memory flashes confirm the gold figure is Emonie, who used a glamour to resemble her.

Auren reveals herself to the stunned crowd, announces her true identity, unleashes her gold and ribbon magic, and frees the Vulmin prisoners. A chaotic battle erupts as Vulmin sympathizers in the audience rise up and join the fight against the king’s soldiers. Auren fights her way toward King Carrick, who grabs Emonie as a hostage. A tremor shakes the arena, and Carrick notes with satisfaction that a new threat called “The Breaker” is coming. Before Auren can reach the king, an old fae named Brennur uses magic to spirit Carrick and Emonie away. Wick calls Brennur a traitor, and Auren knocks him unconscious for later interrogation. Just then, a tremendous sound shakes the city, signaling “The Breaker’s” arrival. Auren and Wick race toward the sound, prepared to fight again.