In Vorath Shah’s ransacked shop, Kingfisher and Carrion search for equipment to make antivenom while suffering from demon venom poisoning. Fisher hallucinates his mother taunting him for being too late, then his deceased friend Merelle accusing him of carelessness. He forces the tiny scorpion remnant of Joshin to produce venom, infuses it with his blood, salt, and shadow magic, and then he and Carrion drink the concoction. They suffer through an hour of agonizing, conscious seizures before recovering.

At Carrion’s apartment, the smuggler finds a note banning him from the Dusty Crab. He pours whiskey into glasses Saeris made—etched with images of Madra’s palace in flames. Fisher examines one, suddenly overwhelmed by how much he aches for his mate. He asks Carrion if he is in love with Saeris. Carrion explains his feelings are complicated: He could have loved her, but his heart is too full of ancient sorrow to make room for her. For the Fae, he says, grief deepens over time rather than healing. Fisher understands. When Carrion asks Fisher to teach him how to shut off pain, Fisher refuses, explaining his own endurance was forged through repeated suffering—a curse he would spare anyone.

Saeris struggles to sleep but eventually enters a dreamlike state and finds herself in a snowy valley. She sees Fisher chopping wood shirtless outside a huntsman’s cottage near Cahlish. When he turns and sees her, his initial smile turns to shock, and he asks if she is dead. They realize they are sharing a dream that feels entirely real. He reveals he had a difficult day in Zilvaren, securing silver and encountering a scorpion demon. He leads her inside the cottage, where Onyx is also present.

Saeris touches Fisher’s ankle, and black ink flows from her fingers, creating a tattoo of a half dagger on his skin—an effect of their mate bond and claiming magic. Fisher carries her to the bedroom. He pleasures her with his mouth, and when his broken hand interrupts them, she commands him to bite her and heal. He bites her inner thigh, saturating her with his venom while stimulating her, then drinks her blood. The combination causes her to experience an overwhelming orgasm. He shows her his hand is completely healed, then they have sex, climaxing together as the cottage walls tremble.

Afterward, they eat stew, and Saeris tells him about finding Foley. Fisher explains the gold plating on Foley’s canines marks a shunned vampire whose fangs were ripped out for refusing to swear allegiance to the crown. He assumes Taladaius has been keeping Foley alive. When Saeris asks about Ren’s hatred for Taladaius, Fisher reveals that Taladaius was once betrothed to Everlayne but abandoned her the night before their wedding to join Sanasroth because he was in love with Zovena.

Fisher awakens in Carrion’s apartment and discovers his hand is completely healed, and the tattoo Saeris gave him is on his leg. Carrion, covered in welts from the antivenom, is shocked at Fisher’s recovery. Fisher explains that Saeris healed him in their shared dream. While changing clothes in Carrion’s bedroom, he discovers the walls are covered in drawings Carrion has made over the years. He recognizes a drawing of Queen Amelia Daianthus, the last Fae queen of Yvelia and Carrion’s mother. He sees other drawings of Fae warriors, creatures, and landscapes from Yvelia—a world Carrion has never seen.

Carrion enters, assuming Fisher thinks he is pathetic for his obsession. Fisher shows him a drawing of the Winter Palace with Daianthus banners and tells him he does not see obsession, but a male longing for a home and people he has never known. He gives the drawing back and tells Carrion to bring it home with him.

Saeris awakens and finds puncture wounds on her thigh, confirming the dream with Fisher was real. On her way to the library, Lorreth intercepts her for their training session. He notices she smells of Fisher and accepts her story about the shared dream. In a cold, featureless training room, Lorreth has them train with staves. Saeris finds her reactions are stunningly fast, and her strength has increased; she matches Lorreth blow for blow.

In the library, paper stargazers greet her. Foley warns her not to interact with them, as they steal hair, which can be used in witchcraft. The hole in the wall has been replaced by a circular window. Foley is condescending, revealing his bitterness over centuries of isolation. Saeris confronts him for wallowing when his friends tried to contact him. Foley insists he received no letters. Lorreth arrives and confirms that he, Ren, Fisher, and Danya wrote to Foley many times, begging him to come home.

Saeris’s frustration causes her magic to flare, making her gloves smolder. She rips them off, revealing glowing, burning runes. Foley identifies the most inflamed rune as the symbol for quicksilver and calls the entire configuration an Alchimeran shield. The shield is a protective rune configuration that prevents Alchemists from being destroyed by their own magic. He gives her the Alchemy book and has her read about mastering quicksilver before sealing its rune. Saeris believes she is ready, but Foley chastises her for forcing her magic rather than forming a partnership with it. His analogy about building a house on shifting sand resonates deeply with her, and she agrees to practice at the forge.

As she leaves, a stargazer cuts her neck and cheek to get her attention, then flies out of the library’s doorway and immediately falls dead, its magic severed. Feeling terrible, she tries to revive it by bringing it back inside, but it remains lifeless. She puts the paper bird in her pocket.

Fisher and Carrion track Saeris’s brother, Hayden Fane, through Zilvaren. Hayden ambushes them with a dagger but misses. He recognizes Fisher’s name and accuses him of murdering Saeris, showing them propaganda flyers calling Fisher the Butcher of Zilvaren. Hayden believes the propaganda but admits he only saw drawings of a body, not the body itself. Fisher grabs him, demanding to know if he wants to see his sister. Hayden agrees but reveals they must first go to the Third so Carrion can say goodbye; from this, Carrion intuits that his caretaker, Gracia, is dead.

They join mourners at a pyre site in the desert dunes. At Gracia’s burning pyre, Carrion throws his last book about Fae creatures into the flames. Fisher explains the three-day vigil ensures the dead do not rise or transition. Overcome with grief, Carrion collapses. Fisher catches him and pulls him into a hug, allowing him a moment to sob.

Back in the city, new posters offer a year’s supply of water as a reward for their capture. Guardians ambush them. They flee to a large square where teenage girls are being rounded up for cleansing day. Enraged at remembering Saeris suffered the same fate, Fisher tells Carrion to get Hayden to safety. He unleashes his magic as corporeal black knives, killing the Guardians in a rage-fueled massacre. Carrion snaps him out of it as a larger army approaches. As they flee, Fisher discovers a massive reserve of magic within himself and unleashes it, blanketing the entire city of Zilvaren in magical darkness.

In the forge, Saeris makes a relic by trading an unknown memory to the quicksilver. The Hazrax appears, a powerful, ancient creature that is Keeper of Silence. It questions her reliance on blood magic and reveals that it previously had a deal with Malcolm: one favor per year in exchange for observation rights. Saeris agrees to the same deal but stipulates it must be renewed annually. The Hazrax accepts but declines Saeris’s offer of a blood oath, dismissing blood magic as crude.

After the Hazrax leaves, a relic it had been levitating drops into Saeris’s hand, causing her magic to surge uncontrollably. Realizing she may destroy the palace, she panics and resolves to run.

In the magical darkness covering Zilvaren, Fisher gives Carrion the Sight to lead them through the chaos. Hayden guides them to a building with a heavy wooden door, knowing the trick to open it despite the darkness. They enter a forge and are immediately attacked by Elroy, Saeris’s former master, wielding a fire iron. Carrion tries to de-escalate, but Elroy demands Fisher leave. Hayden reveals Fisher claims Saeris is alive. Carrion, emotionally frayed from Gracia’s funeral, defuses the argument. Elroy expresses condolences about Gracia, and Fisher declares his unbreakable promise to bring Hayden home. Elroy concedes but insists Hayden must choose. Hayden confirms he wants to go.

After hours of explanation to Elroy and Hayden, Fisher confronts Elroy about his knowledge of the Fae. Elroy admits he has always known about the Fae and about Carrion’s true nature. Carrion is outraged that Elroy never told him. Elroy explains he was bound by rules passed down from his father, similar to how Gracia’s bloodline, the Swift family, was charged with protecting Carrion. He reveals a secret door in his forge, opened with a drop of his blood, and leads them down a long granite staircase of 1,223 steps.

At the bottom is a vast cavern filled with metal goods, armor, and treasures. At the center is a huge, recessed pool. The quicksilver voices in Fisher’s head become extremely loud. Elroy reveals the pool contains a dangerous amount of quicksilver.

Saeris sprints to the familiar quicksilver tomb in Ammontraíeth, her power raging out of control. The quicksilver in the pool calls to her, telling her to join it. Unsure if it will kill her or save her, but with no other choice, she decides she must enter the pool to bond with the magic. She lets her internal walls down and allows her immense power to flood her senses. She stops fighting the magic and finds she can control it with ease, opening a portal. She steps into the physical quicksilver pool.

The quicksilver climbs her body as a powerful, singular voice speaks in her mind, challenging her right to its power. The voice calls her a pretender and unworthy. She stands her ground, declaring she is worthy. The voice tries to trick her, saying power is always a weapon, then asks what she would do to prevent a looming dark horizon. It asks if she would die, kill, or give up that which is most dear to her. She agrees she would die and kill, but when asked to sacrifice what is most dear, she thinks of Fisher and refuses.

Expecting to have failed its test, she is surprised when the voice approves. It explains that every Alchemist must have something they are afraid to lose. This is the final test required to bond fully with quicksilver and become a true Alchemist. She cries tears of silver as the pain recedes. The voice declares the pathway clear and bestows a gift, warning that in the end, the gift will be her end. She is violently thrown backward out of the pool, hits a wall, and loses consciousness.