Winter rests in LW-12 and watches the people and wolf soldiers prepare for rebellion. She suddenly spots Jacin in the crowd and follows him into the woods. Winter sees an old woman who stops her and claims that Jacin left a message and a gift. The woman gives Winter a box of sour apple petites, and they both eat one. Winter realizes the woman is Levana in disguise. Levana reveals that she poisoned the candy with a mutated form of letumosis and plans to use Winter to spread the disease to the rebels. Levana admits that she resents Winter’s beauty, her father’s love, and the people’s adoration. After trying to warn her friends, Winter collapses in the forest.

Scarlet realizes Winter is missing and asks Alpha Strom to help find her. After Strom tracks Winter’s scent into the forest, Scarlet finds her unconscious on the ground. Strom immediately smells disease on her and warns Scarlet not to get too close. Scarlet then notices the red-ringed blisters on Winter’s arm and realizes she has letumosis. She remembers that Levana has an antidote. They must keep Winter alive until they can get it, but the disease is progressing faster than usual. Strom says Winter may survive longer in a suspension tank. Scarlet rushes her to the sector’s clinic. The doctor agrees to prepare the tank. Strom insists they move the tank outside so Winter can remind people what they are fighting for. The doctor warns that he only has one tank. Scarlet looks at her own arm and discovers plague marks.

Wolf wakes from violent dreams that mix memories of Scarlet, his family, and his brother with new animal hunger. He finds himself strapped inside a medical tank while technicians remove needles and equipment from his body. A thaumaturge, Bement, tells him he has been fully transformed into one of Levana’s monsters and that Levana wants him to serve as a guard for her coronation. Wolf realizes with horror that they have completed the final surgery, turning him completely into a wolf soldier. He struggles to distinguish between memory and instinct. His feelings for Scarlet are confused as he remembers only their most painful memories. When Bement asks what he would do if he saw Scarlet now, Wolf answers that Earthens are sweet. Satisfied, Bement decides he is ready to serve the queen.

While Cinder works to repair Iko with the limited parts they have. They talk about Wolf, Kai, Adri’s trial, and the anti-Lunar device Garan created. Cinder suspects that Garan hid more secrets in Iko’s old software. Jacin admits that he told Levana about Garan’s device in exchange for his life. Cinder realizes that Winter may be in danger because of it. Jacin brings everyone to the mansion’s theater, where they watch Levana’s latest broadcast claiming that Cinder is dead. Eighty-seven sectors are in revolt or barricaded. They form a plan. Thorne and Cress will sneak into the palace to disable the barricades and broadcast Cinder’s video, while Cinder, Iko, and Jacin will use terrain speeders to reach nearby sectors and organize the rebels. The plan changes again when they discover that LW-12 is quarantined. Surveillance footage shows that Scarlet is alive, the wolf soldiers are with her, and Winter is inside a suspension tank.

Wolf studies his altered body after the latest surgery and realizes he has become exactly what he always feared. His face, hands, feet, and hunger have all changed. Wolf feels disgust and helplessness. Thaumaturge Bement tests his obedience by showing him a tray of meat and then punishing him with intense pain when he reaches for it without permission. She explains that good behavior earns rewards and disobedience brings suffering. Wolf submits, calls her Mistress, and forces himself to obey.

Kai waits by Artemisia Lake and watches the sunrise. He knows that the body Levana presented as Cinder’s is false and hopes she is still alive. Torin joins him, and they discuss consequences should the rebellion fail. Kai reveals that he recommended Torin be nominated as a candidate for the Commonwealth’s next ruler if Kai dies without an heir. He also explains his plan to stay close to Levana long enough to secure the letumosis antidote, then order Earth’s military to bomb Artemisia with him and Levana still inside, should all else fail. Torin is horrified, but Kai will not allow Levana to rule Earth.

Inside the mansion, Cress and Thorne prepare disguises so they can enter the palace as aristocratic guests. Jacin hurries everyone along. The group then splits up. Thorne and Cress head for the palace to break into the broadcast system, while Cinder, Iko, and Jacin prepare to enter the medical and research clinic. They hope to find both the antidote for letumosis and some way to help Winter.

When they arrive, they find the clinic filled from floor to ceiling with suspended-animation tanks. The tanks hold unconscious shells, mostly children, kept alive for their blood. Everyone is horrified—even Jacin, who knew about the clinic’s existence.

Cinder, Jacin, and Iko find the disease research and development lab and search it for the letumosis antidote. Iko discovers cabinets full of labeled vials, and the group quickly loads as many trays as they can onto a rolling cart. They hear a thaumaturge and others arrive on the floor. Cinder offers to fight, but Iko, who is immune to Lunar manipulation, insists on drawing them away. Iko walks into the hallway alone and distracts the group, giving Cinder and Jacin a chance to escape with the antidote. Gunshots fire as and Jacin and Cinder flee.

Cress and Thorne arrive at the palace and blend easily into the crowd. Cress feels nervous returning to the palace, but Thorne encourages her to act like she belongs there. They draw attention from flirtatious Lunars, and Cress notices nearly everyone using glamour and manipulation, as she is immune. Cress loses sight of Thorne. She finds him again as a beautiful Lunar woman kisses him.

Thorne tells the woman he loves her. Cress hides and watches, furious and hurt. Thorne finds Cress and tries to explain that he was manipulated, but Cress’s jealousy and heartbreak spill out. They argue, and a guard orders them toward the great hall. Thorne steers Cress into an atrium. Cress admits that she never wanted to be just another girl to Thorne. Thorne kisses her. He tells her the Lunar woman made herself look like Cress. Cress demands an explanation for his love confession, and the atrium door opens.

A guard interrupts Cress and Thorne and orders them back into the halls. Cress tries to act normal, but she breaks into nervous laughter, which turns to panic when the guard tells them to stop. Thorne grabs Cress’s hand and runs with her through the palace until they reach the servants’ halls. He hides her behind electrical cords and tells her to make her way to the security center while he distracts the guards. Cress begs him not to leave. Thorne kisses her, hands her his gun, and runs off. Guards chase him, and Cress hears the guards catch Thorne and drag him away.

Jacin and Cinder race across Luna in a terrain speeder loaded with trays of letumosis antidote. They reach LW-12, take the antidote for themselves, and face an armed crowd that does not trust them. Scarlet recognizes Cinder and confirms that Winter is alive but extremely sick. Jacin pushes through the crowd to Winter’s suspension tank. He finds her surrounded by flowers and barely alive. A doctor warns that opening the tank will kill her quickly if the antidote fails, but Scarlet insists Winter would trust Jacin. The doctor drains the tank, Winter begins breathing on her own, and Jacin waits beside her until she opens her eyes. He gives her the antidote.

Winter wakes after taking the antidote and slowly becomes aware of Jacin, Scarlet, Cinder, the wolf soldiers, and the gathered crowd around her tank. A doctor checks her blood and confirms that the antidote is working and that her body is already fighting off the disease. Cinder begins organizing the distribution of the remaining antidote to the people of LW-12. Still weak and covered in gel, Winter lets Jacin carry her into the clinic so she can wash and recover. They reconfirm their love for each other.

After hiding in a storage cabinet, Cress forces herself back into the servants’ halls and tries to reach the control center. She spots a guard by the elevators, distracts him by knocking over a heavy statue, then escapes into an elevator under gunfire. The elevator stops on the Earthen diplomats’ floor, and Cress slips out before she is trapped with them on the way to the coronation. An Australian diplomat questions her and threatens to call a guard. Kai appears and vouches for her. Alone with Torin, Cress breaks down, explaining that Thorne has been captured and that Cinder is alive. She tells them urgently that she needs to get to the control center to broadcast her video. Kai decides to help, and Torin agrees to buy them some time before the coronation.

Kai and Cress hurry through the palace toward the control center. Kai warns that he cannot help for long. At the control wing’s entrance, Kai distracts the guard by pretending he needs to find a missing brooch for the ceremony. As the guard opens the vault, Cress slips past and runs for the control center. She breaks into the room and works as quickly as possible. Cress changes the palace security codes, locks down the armory, schedules the tunnel barricades around Artemisia to retract, and uploads Cinder’s video to the royal broadcasting system. Guards enter, but she hides behind the equipment and avoids discovery. Though trapped inside, she finishes her work.

After washing and changing clothes, Winter leaves the clinic and finds the people of LW-12 cheering for her recovery. Cinder shares that Cress has brought down the tunnel barriers, allowing the rebels to march on Artemisia. She quickly lays out a plan to split the growing force into groups, gather more fighters and supplies, and converge on the capital. Cinder orders Jacin to use the terrain speeder to rally more nearby sectors, but he refuses to leave Winter behind. Winter insists on going with him because the people will listen to her. After arguing, Jacin gives in. The royal coronation broadcast begins. Winter turns the people’s attention away from Levana’s voice and toward Cinder, declaring the beginning of their revolution.