In the greenhouse, Florence works on her alchemy project involving emberfern and overhears Allenvale and Rodriguez  arguing about “jeopardizing” a critical mission. They defer the discussion when they spot Florence. Professor Allenvale praises Florence’s work and offers her a scholarship for a summer research retreat at the Somnaria Institute. Florence is thrilled, but doubts Lady Avari would allow it. Nyxaris communicates with Florence telepathically, promising to ensure she can go if she wishes.

Later, while flying with Nyxaris, Florence asks why dragons need riders. He theorizes they served as interpreters and reveals he once had “soul-bound” highblood riders—a highblood soul placed into a blightborn rider body. The memory is painful for him. When pressed, Nyxaris confesses that his last rider was killed because of him, after which he began to question his allegiances and goals. Molindra then came to him and offered a new purpose; in return, he gave up everything and accepted being turned to stone.

Nyxaris also mentions that he recently saw another dragon in the skies—he first thought it was Vorago, then wondered if it might be Molindra—but the dragon fled before he could make contact. The training session ends as Florence’s thighs begin to ache from the ride, and Nyxaris matter-of-factly advises her to ice them.

While practicing archery with blightborn Professor Stonefist, Florence dreads the engagement ball with Kage scheduled for that evening. Medra finds her, and Florence confesses she feels nothing for Kage and wishes she did not have to go. She also reflects on the increasingly vivid and erotic dreams she has been having about Nyxaris. The dragon, sensing her anxiety, communicates that the betrothal is merely a temporary shield against Viktor. Medra helps her get ready, and they head to the ball.

Blake prepares for the Avari ball while studying the book of dark magic given by Rodriguez. He focuses on the “Spell of Twin Hearts,” a dangerous ritual that could merge him with a second dragon to gain control over his own violent, inner beast, but which could also kill him. His missing eye has regenerated, but it sometimes flashes red, a sign of the dragon’s influence.

Theo and Visha arrive at Blake’s chambers. Visha is distraught, having received a letter stating her young nephew, Arjun, went “feral” with a mysterious illness, attacked his family—biting his sister, his mother, and his father—and was killed. The man who killed him in self-defense was then executed by her family. Arjun’s sister, mother, and father are now at risk, suggesting a spreading plague.

At the ball, Blake spots Medra looking beautiful in a black and silver gown and the sight of her triggers a possessive, draconic urge in him. Blake resolves to risk his own life to protect Medra from the monster inside him, even if it means attempting the Spell of Twin Hearts.

On her way to the Avari engagement ball, Regan intervenes when she sees her Bloodguards, led by Silvio, abusing Dani. Professor Rodriguez is already there, defending the girl. Regan’s own revulsion at the girl’s condition drives her to confront Silvio; Rodriguez then reveals mid-confrontation that Dani is Professor Stonefist’s niece, a political complication that reinforces Regan’s decision. She orders Silvio to stand down and sends Dani to the infirmary. For a moment, she identifies with Dani, who is under thrall, recognizing in Dani her own powerlessness.

At the ball, Regan feels isolated and despised. She watches Kage and Florence dance, accepting that she is trapped and Viktor will never release her brother, Persis. As she tries to leave, Kage stops her and insists they dance. He holds her possessively and tells her he is ending his engagement to Florence that night. He praises her for saving Dani, seeing it as proof of her inner goodness, and asks her to meet him in the Dragon Court at midnight so he can help her. Though she knows an escape from her misery is impossible, Regan does not refuse.

Kage finds Florence on the terrace and ends their engagement. Florence is immensely relieved. Freed from her social obligations, she heads to the library to work on her alchemy essay.

On her way back to her room, she hears Neville, in distress. She finds him cornered by a Bloodguard, Brocklin, whose skin is discolored with black veins and whose eyes are milky white, signs he has been infected by the mysterious plague. Regan appears and attacks Brocklin twice with her stiletto heel—first freeing Neville by driving the heel through Brocklin’s wrist, then stabbing it into the hollow where his neck meets his skull after Nyxaris smashes through the ceiling and distracts him. Regan then shoves Brocklin toward Nyxaris so the dragon can incinerate him.

During the chaos, Regan is injured by falling debris. Kage arrives, scoops up the unconscious Regan, and leads Florence and Neville through the castle toward the safety of the Avari tower.

Blake and Medra leave the ball and return to his room, where they have passionate sex. During the encounter, Blake’s inner dragon takes over, and he becomes violent, growing scales and feeding on Medra’s blood. His wings burst from his back, destroying the room as he nearly kills her.

Horrified, Blake wrests back control and finds Medra unconscious and dying. Desperate, Blake feeds her his own blood to heal her. While she is still passed out, he whispers that he loves her. Believing he is a monster who will inevitably harm her again, Blake covers the broken window, gently lays Medra on the bed, and leaves with his book of dark magic, determined to end the dragon inside him even if it kills him.

Medra awakens in Blake’s wrecked room with fragmented memories of the night. She cannot remember Blake turning into a dragon, but feels strangely energized. Her mother, Orcades, contacts her telepathically, warning of a coming danger she describes as a “wave of red.” Orcades recognizes the situation as analogous to a plague her own father once unleashed in Valtain, within Aercanum (where Camelot is located).

Blake returns, looking exhausted and with a crimson tint to his eyes, but he evades Medra’s questions. Their conversation is interrupted when Visha and a bloody Theo burst in. They were attacked by an infected First Year, whom Visha was forced to kill. Moments later, two more infected students attack the room, and the group kills them. Blake takes charge, ordering the Drakharrow tower sealed and systematically cleared. He promises to help Medra and Theo find Florence and Vaughn once their own tower is secure.

Kage carries Regan into the Avari tower, followed by Florence, Neville, and Professor Rodriguez, who leads a group of terrified First Years. The First-Year tower has been overrun by infected students. In the Avari infirmary, Neville begins growling at an already injured highblood girl named Jacklyn. Jacklyn suddenly turns and attacks the healer, Elycia, revealing she is infected. Kage kills Jacklyn instantly.

Kage declares that anyone bitten must be killed to stop the spread, but Rodriguez and Florence protest. Florence realizes Neville can sense the infection and proposes using him to identify the afflicted. They test her theory in the crowded common room, where Neville singles out a boy named Andrew who is hiding a bite mark. Kage executes Andrew and puts the tower on lockdown. Back in the infirmary, Elycia examines Jacklyn’s body and suggests that the plague may not be a traditional illness, but a magical poison that spreads by the bite, causing unnatural blood clotting leading to a desire to consume more blood. Florence thinks if the toxin is alchemical, mirthleaf could be an antidote. Florence is tasked with preparing a tincture.

With Drakharrow tower secured, Medra and Theo prepare to leave to find Florence and Vaughn. Orcades contacts Medra again, describing “two fools” trying to break down the barricade between realms using blood magic and necromancy as the source of the plague.

As Blake, Medra, and Theo are about to leave, two late-returning students, Collette and Jareth, enter the common room. Blake senses something is wrong with Collette, claiming he can “hear her blood is rotting” (339). He discovers a bite mark on her arm and executes her before she can turn. He then orders that all new arrivals be inspected and the bitten be isolated. Visha agrees to stay and command the tower, allowing Blake, Medra, and Theo to depart on their search.

Blake, Medra, and Theo find a corridor littered with mangled corpses. They are suddenly ambushed by a first wave of Bloodguards led by Quinn Riley, with Edward Ashveil among them. A second wave led by Silvio Santos cuts off their retreat. Outnumbered, Theo and Medra are captured. With a knife to Theo’s throat, Quinn forces Blake to surrender.

The trio is taken to the refectory, where Viktor Drakharrow waits on a makeshift throne. Silvio strikes Medra, and an Avari Bloodguard named Cade is ordered to restrain her. Blake senses Cade is infected and demands he release her. Viktor confirms Blake’s ability to sense the plague, mockingly asking if he has told Medra about the “dragon lurking behind those red pupils” (348). Viktor then reveals that the statue of the dragon Vorago in the Dragon Court is now a pile of red ash, implying Blake has absorbed its power. Horrified, Medra turns to Blake and asks what he has done.