Sylina recalls her initiation into the Arachessen at age 10. The Sightmother gave her the name Sylina, and another Sister applied a chemical called Marathine extract to Sylina’s eyes as the first step in a year-long process of losing her sight to gain thread perception. Sylina endured the pain without screaming by biting her tongue, leaving a permanent scar.

In the present, Sylina gathers with 40 Sisters at the Arachessen’s headquarters, the Salt Keep, weeks after the invasion. The 25-year-old notes the empty chairs for the Sisters, including Raeth, who have been killed by the invaders. Although the Arachessen believe it is their ultimate mission to oppose the Pythora King who rules the country of Glaea, most of the Sisters worry how the invasion will impact their nation. Obitraes, the vampires’ homeland, hasn’t issued a formal declaration of war, which could indicate that the invaders’ leader is acting independently.

Asha suggests the invasion might be a divinely sanctioned purge. Sylina is angry at Asha for dismissing the human cost and for ordering the retreat that saved the vampire leader. Asha reminds Sylina that Arachessen act on their goddess’s will, not morality, and notes that Acaeja is the only deity in the White Pantheon worshipped by humans who tolerates Nyaxia. The Sightmother ends the argument but agrees that the conqueror is troubling. She asks to speak with Sylina privately.

The Sightmother acknowledges Sylina’s grief over Raeth’s death and suggests that Sylina has a strong sense of justice because she joined the order at age 10, much later than most Sisters. At times, this sense of justice conflicts with Sylina’s duties as an Arachessen, who are meant to serve only the goddess’s will.

The Sightmother says she communed with Acaeja and that the goddess showed her that the conqueror’s actions threaten the natural order and the White Pantheon. She orders Sylina to infiltrate the conqueror’s army, learn his intentions, and kill him.

The Sightmother explains that the conqueror is from the vampiric House of Blood, which relies heavily on human seers. The conqueror has a seer, but Sylina must displace her and take that position. The Sightmother directs Sylina to travel via magical pools to reach the conqueror’s location. Sylina eagerly accepts the mission because she wants to prove that she belongs among the Arachessen.

Sylina recalls how the Sightmother destroyed one of her paintings when she was 10. In the present, she travels via magical pools and emerges near the vampire encampment. She identifies the conqueror by his powerful, angry aura.

After two days’ surveillance, Sylina identifies an older human woman as the conqueror’s seer. She follows the woman to a remote lake where she prepares to pray. Sylina uses thread magic to teleport behind the seer and ambush her. The seer anticipates the attack and recognizes Sylina as an Arachessen “cultist.” They fight briefly, but Sylina easily overpowers her. Sylina questions why the seer helps the conqueror. The seer taunts Sylina about joining the Arachessen late, and Sylina slits the seer’s throat.

The vampires discover their seer is missing. The conqueror becomes furious and orders an extensive search that continues for days. Sylina goes to a nearby town and makes herself conspicuous in a bar. Two vampire soldiers arrive searching for their seer and notice that she’s dressed like a seer of Acaeja.

Sylina rents a room at the inn and makes herself vulnerable to capture. A stocky vampire soldier with ash-blond hair breaks into her room. Sylina feigns terror and strikes the soldier with a candlestick, gashing his cheek. Angered, the soldier cuts her forearm with a dagger. The wound allows him to use blood magic on Sylina, and he renders her unconscious.

Sylina awakens in a chair inside the conqueror’s tent. She notes the scent of snow and iron that clings to the vampiric leader as well as the signs that he’s been cursed, such as his horns. The conqueror touches her cheek and reaches for her blindfold, but she stops him. To avoid provoking the Arachessen, he decides to release her.

Sylina lies, claiming to be a fugitive from the Arachessen who needs protection and cannot flee her country due to the invasion. The conqueror changes his mind and offers a deal. If she will serve as his seer, he’ll protect her from the Arachessen and give her her freedom after his campaign ends. Sylina expresses her disbelief that he will keep his word, but he insists he doesn’t lie and says he has “a soft spot for caged birds” (37).

Sylina is shackled to a post in a tent. She performs Threadwalking, a deep immersion into the threads, to sense the thoughts and emotions of soldiers throughout the camp. The conqueror sends Erekkus, the vampire who abducted her, to bring her food. The soldier shakes her awake, and she warns him that interrupting her Threadwalking could have killed her. Erekkus tests her sightless perception of her surroundings and is unsettled by her accuracy.

Erekkus claims Atrius has earned his trust over centuries and always keeps his word. When Sylina asks why the House of Blood wants to conquer her country, Erekkus becomes defensive and cold. He leaves, stating Atrius will see her the next day. Sylina sleeps and wakes to find Atrius in her tent.

Atrius unlocks the shackles on Sylina’s wrists and ankles and bluntly assures her he will not assault her when she tenses at his touch. He leads her from the tent, warning that if she tries to escape, he will kill her. As they walk through camp, Sylina feels the hungry stares of the other vampires. Atrius warns her never to leave her tent without him or Erekkus.

Atrius takes her to a lakeshore near where she killed the previous seer and demands she perform a seering. To make him feel like he has earned her trust, Sylina feigns reluctance and then pretends to be convinced by his promise of protection. They shake hands to seal their deal. Atrius shows her a map of their next target, Alka, a city-state ruled by a warlord named Aaves. With Atrius’s help, Sylina prepares a ritual fire. She kills a rabbit with his bow, offers the animal’s blood to Acaeja, and enters a trance.

In her vision, Sylina walks on a silver thread on the surface of a body of water. She sees Alka and witnesses branching threads: Under a full moon, blood overwhelms the scene. Under a crescent moon, the cliffs appear less blood-soaked, and human bodies fall into the sea. The Weaver’s voice tells her she is looking in the wrong direction.

Sylina follows a path backward into a vision of a snowy mountain under an eclipsed moon. She sees a younger, hornless Atrius with another man in ornate armor. The goddess Nyaxia appears before them and kills Atrius’s companion. Atrius kneels in grief, begging the man to wake.

Atrius forcibly wakes Sylina from the dangerous trance. Her feet are bleeding from the vision’s intensity. To sabotage the invasion, Sylina lies and tells Atrius to attack Alka under the full moon. When Sylina reveals the vision she saw of his past, Atrius becomes intensely angry. He forbids her from ever seering about him again and storms away.

Later that night, Erekkus gives Sylina magical medicine for her wounded feet. The following night, the army breaks down camp to move toward Alka. Erekkus mentions fighting the Wraiths of Slaede, tortured vampire souls turned into monsters, and Sylina asks if Atrius was his commander on that mission. The question triggers deep shame and regret in Erekkus. He praises Atrius as a great leader and then alludes to the low status of the House of Blood, whose members are unpopular in Obitraes due to an old curse involving “[a]ngry goddesses and entitled kings” (62). Erekkus notices Sylina watching Atrius and teases her. He tells her she fits the profile of women Atrius is drawn to because she’s beautiful, mysterious, dangerous, and a “mistake.”