Following Gabriel’s fall, the vampires Kiara and Kane Dyvok capture Dior. Kane wishes to kill her, but Kiara intervenes, realizing Dior must be valuable since the Voss faction was also pursuing her. Kiara incapacitates Dior and takes her prisoner to present to their Count. 

During their journey, Dior awakens in the care of a thrall named Joaquin. Recognizing him as the beloved of a girl she previously helped, Dior tries to convince him to free her, but his fanatical loyalty to Kiara is unshakable. After three nights, they reach a hut with other thralls. While the vampires sleep through the day, Dior uses hidden lockpicks to free herself from her manacles. She steals a horse and creates a false trail by galloping into a forest, then leaping from the saddle into the trees. As her pursuers follow the horse’s tracks, Dior escapes on foot, believing she is free.

Dior’s escape attempt ends when she is caught by Joaquin and the brutal thrallsword, Shae. After Dior fights back fiercely, an enraged Shae attacks her, ignoring Joaquin’s pleas that their mistress wants her unharmed. When Joaquin defends Dior, Shae fatally stabs him and kills his hound, Matteo. Just as Shae turns back to Dior, Kiara arrives and violently executes him for his insubordination. 

When Kiara refuses to save the dying Joaquin, Dior presses her own bloody hand to his chest, miraculously healing his wounds and shocking Kane. Kane grabs Dior, but her blood burns him, shocking him further. Kiara overpowers Dior, threatening her with torture if she runs again, and reveals their destination is the court of Priori Nikita the Blackheart in Dún Maergenn. Realizing this is where Mother Maryn rests, and therefore the exact place she needs to go, Dior ceases her resistance and follows her captors.

After a two-week journey south, Kiara and Kane deliver the captive Dior to a massive Dyvok convoy overseen by another vampire, Soraya. Dior is horrified to find the convoy consists of over a thousand caged refugees, the last of the Aveléne rebels. To make room for her in a crowded wagon, Kane publicly feeds on and kills a young man. 

Once imprisoned, Dior is reunited with other survivors, including a girl named Isla, who tells her that Frère Lachlan abandoned the children he was meant to protect. Joaquin coldly rejects his former love, Isla, revealing how much he has changed. Dior has an emotional reunion with Baptiste Sa-Ismael, who is also a prisoner. When she tries to console him over the death of his partner, Aaron de Coste, Isla reveals the truth: Aaron is not dead but has been turned into a vampire and is being transported in a chained iron box on one of the wagons.

For three weeks, Dior, Baptiste, and other prisoners are transported to the ruined city of Dún Maergenn. Each night, they are forced to listen to the screams of Aaron. Since he’s been turned into a vampire, his silver-inked tattoos cause him immense pain, and his captor, Kiara, has them flayed from his skin daily, only for them to regenerate by the next dusk. Upon arrival in Dún Maergenn, the convoy navigates the ruined capital, where Kane feeds captives to a starving mob of foulbloods to ensure safe passage. Inside the castle bailey, the prisoners are sorted by their skills. Baptiste, a smith, is taken to the forge. When Dior is deemed useless and about to be condemned, Kiara personally claims her. With no other choice, Dior takes the Wolfmother’s hand as the captives are separated.

Kiara leads Dior into the Dyvok stronghold’s feasthall, a horrific “Court of the Blood” where vampires drink from live humans suspended from the ceiling (548). Kane and Soraya follow, carrying the captive Aaron in an iron coffin. After warning Dior to be silent and obedient, Kiara presents herself before her father, Laerd Nikita Dyvok, and her aunt, Contessa Lilidh the Heartless. Lilidh greets Kiara with thinly veiled hostility, crushing her throat for her tardiness before Nikita intervenes.

Kiara announces her great triumph, claiming she has killed Gabriel, which sends the court into a celebratory uproar. For a second gift, and to earn her father’s favor, she presents the newly turned Aaron. Nikita expresses his pride in his daughter. As Kane and Soraya open the iron coffin to release the fledgling, Aaron immediately lunges at Kiara’s throat.

When the coffin opens, a starved and desperate Aaron takes his one chance to fight Kiara. He wounds her, but in his weakened state he’s no match for her, and she brutally defeats him. Her father, Priori Nikita, stops her from delivering the killing blow, impressed by Aaron’s spirit. Nikita offers Aaron a chance to pledge allegiance, but Aaron defies him by spitting blood on his signet ring. Taking this defiance as proof of worth, Nikita declares Aaron “Untamed,” forcibly feeds him his own powerful blood, and snaps his neck to begin his transformation into Nikita’s bloodslave.

The attention of the court turns to Kiara’s other prize, Dior. Lilidh tests Dior’s revealed healing ability by forcing a thrall to stab herself three times. Commanded to demonstrate, Dior successfully heals the dying thrall but lies about the nature of her powers. After a brief power struggle with her brother, Lilidh claims Dior as her own. She cuts her own throat and forces Dior’s lips to the wound. To survive, Dior drinks the ancient vampire’s blood, the first step toward subjugation as an enthralled vampire.

Imprisoned in the Dún Maergenn dungeons after being forced to drink Lilidh’s blood, Dior discovers a small blood moth on her arm, which is revealed to be a fragment of Celene. Through a simple system of taps, Dior learns that Gabriel’s fate is unknown and Celene is too injured to help her escape. Her despair deepens when a chained and broken Aaron is thrown into the opposite cell, a valuable high-blood prize for the vampires. Kiara informs Dior that in two nights she will be forced to serve Lilidh. After Dior falls asleep, the moth-fragment of Celene flies off, intent on a new mission. Celene reveals that she was brought to the fortress by fate and now intends to locate and awaken Mother Maryn, the eldest and most powerful of the Esana, who slumbers deep beneath the château.

Dior awakens in a dungeon and communicates with a tortured Aaron in a nearby cell. He reveals that Baptiste is alive but warns Dior not to share any escape plans with him. Aaron explains the terrifying nature of the vampiric blood bond, stating that after three nights of drinking, he will be completely subservient to Nikita and could be commanded to kill his beloved Baptiste. Dior confesses that Lilidh has started to bind her as well. A maidservant named Worm escorts Dior to a bathhouse to prepare her for an audience with the Contessa. The bath is interrupted by Count Nikita, who arrives naked and covered in fresh blood. He joins Dior in the tub, expressing a possessive and predatory interest in her, tempted to taste her “venomous” blood despite having given his sister, Lilidh, permission to claim her. Just as Nikita becomes physically threatening, Worm intervenes, claiming her mistress is waiting. Nikita relents, allowing Dior to leave but reminding Worm that he is the true master.

A maidservant named Worm forcibly dresses Dior as a noblewoman before taking her to meet Lilidh Dyvok. Dior witnesses the aftermath of a massacre committed by Nikita and is then shown a horrifying auction where Soraya sells human prisoners to other vampires. On a balcony, Lilidh interrogates Dior, asking if she knows the name Esani. Dior lies, so Lilidh uses her power to force Dior to drink her blood for a second time, leaving her one step from becoming a thrall. Lilidh promises to have the truth from her dreams the next night. Back in her cell, a dazed Dior questions the narrator, Celene, about whether she pushed Gabriel to his death. The narrative breaks to show Celene is lying to Jean-François in the present, though in the past she denies it to Dior. Recovering her senses, Dior declares her intent to escape that night, revealing a hidden hairpin to pick her cell lock.

Guided by Celene’s mote, Dior picks her cell lock and violently neutralizes the jailor. Disguised as a servant, she navigates the bustling dún, narrowly avoiding Kane. She then runs into Joaquin, who recognizes her but helps her and allows her to pass. On her way out, she is horrified by the sight of a massive pit filled with the bones of the vampires’ victims. Reaching her intended escape route—a well leading to the sewers—Dior sees Baptiste working in the forges. Deciding she cannot abandon him, she approaches and convinces him to escape with her. Baptiste agrees to meet her at the well. However, as Dior picks the well’s lock, she is ambushed by Kiara and her thralls, who were led there by Baptiste. Kiara reveals that Baptiste was already her thrall, as she had fed him her blood to save his life after their fight at Avelène. Crushed by the betrayal, Dior surrenders and is recaptured.

Celene Castia explains to Jean-François why Mother Maryn was asleep. After their crusade failed and their leader Illia was destroyed, four ancient vampires known as the Faithful—Maryn, Wulfric, Jènoah, and Oleander—made a pact. They scattered to search for the Redeemer’s lost bloodline, with only two remaining awake at a time to ease their immortal burden. After leaving the imprisoned Dior, Celene searches Dún Maergenn as a moth and finds an Esana sigil, confirming Maryn’s presence. She then witnesses the subjugation of Aaron de Coste, whose silver tattoos have been carved from his skin. Nikita Dyvok attempts to break Aaron, who defiantly refuses to submit. To force his compliance, Nikita tells Aaron a story from his cruel childhood to impart a lesson: Love is a weakness an enemy will exploit. By threatening the life of Aaron’s lover, Baptiste, Nikita forces Aaron to surrender. The chapter ends as Aaron kneels, calls Nikita “Master,” and is compelled to drink his blood.

Imprisoned and bruised, Dior is dressed in fine clothes and led by Kiara to Nikita’s court. Along the way, Dior realizes with horror that the vampires are feeding human remains to the mortal population. When confronted, Kiara justifies their cruelty as a product of centuries of being hunted by humans. In the Hall of Plenty, Dior witnesses Nikita formally accept a fully enthralled Aaron de Coste as his bloodsworn. The ceremony is interrupted by the arrival of the Voss twins, Alba and Aléne, known as the Terrors. They have come under a banner of peace on behalf of their father, the ancient Fabién. The twins claim Dior is Fabién’s property and offer Nikita 2,000 mortals in exchange for her, subtly reminding him of his dwindling food supply. Nikita agrees, but only if they kneel in submission. They refuse, and it is revealed that Fabién is speaking directly through one of their foulblood servants, confronting his rival from afar.

The Forever King, Fabién Voss, speaks through the corpse of a dead child, offering Priori Nikita 2,000 mortals in exchange for Dior. Fabién claims Dior belongs to him and positions his legions nearby as a veiled threat. The offer creates a deep rift between Nikita, who sees the practical advantage, and his sister Lilidh, who believes Dior holds a far greater, unknown value. The siblings’ argument escalates publicly before they dismiss the court. Alone, their conflict turns violent when Nikita attacks Lilidh. She retaliates with her own formidable power, reminding him of his dependence on her and her allies. Nikita storms out, giving Lilidh an ultimatum to prove Dior’s worth.

To reassert control and complete her subjugation of Dior, Lilidh makes her drink her blood again. Dior’s will breaks completely, and she pledges herself to the vampire. As a final, brutal test, Lilidh commands her ladies to beat a servant girl named Worm for a past failure. She then orders Dior to join in the punishment, and Dior obeys without hesitation. The narrator, Celene, watches in horror, realizing all hope is lost. She flees into the wilderness, alone and despairing, and calls out for Gabriel.

The historian Jean-François de Chastain taunts his prisoner, Celene Castia, about her vanity and failures. Celene retaliates by questioning him about his death at the hands of the woman he calls “Mother.” When he dismisses her, she uses her power to telekinetically shatter his goblet and the room’s light source, plunging them into darkness and causing Jean-François a moment of intense fear. After his guards arrive with torches, Celene warns him not to judge her people, correcting their name from the Faithless to the Faithful. She recites a prophecy familiar to the historian but stuns him by adding a previously unknown final couplet: “By sacred blood, or else by none; / This blackened veil shall be undone.” Celene then refuses to continue her tale, insisting Jean-François must speak with her brother, Gabriel, for the next part of the story. A furious Jean-François agrees to leave, and she asks him to give her love to Gabriel.