Iudex investigator Signum Dinios Kol (Din), an imperial engraver—that is, a criminal investigator whose mind has been augmented to possess perfect recall—travels by carriage with his superior, Ana Dolabra, toward the city of Lacanthim. Ana, who wears a blindfold to prevent her extraordinarily powerful analytical mind from being overwhelmed by too much sensory input, complains loudly that their assignment, the murder of a gentry girl, commands attention only because of the victim’s social status. Din privately recalls their orders, which warn of widespread social strife. He reminds Ana that the case is urgent because the suspect, Castus Armenta, and the victim are from two different gentryclans (aristocratic families) who are now on the verge of war.

Their journey is impeded by a traffic blockade. Impatient, Ana orders their pilot to drive off-road through the surrounding bean fields, which are harvested by drokha-cats—strange, cat-like creatures with human hands. As they approach the city, they discover the source of the blockade: Armed forces from the Armenta gentryclan have surrounded the town. Ana deduces that the situation is a stalemate, with the Armenta family trying to free the suspect from jail while the victim’s family is trying to reach him for their own retribution.

Din and Ana arrive at the murder scene to find a tense standoff between the Armentas and the Buravs, just as Ana predicted. After Din bluffs his way past Armenta forces, they meet the victim’s father, Burilis Burav, who demands his daughter’s body and insists that the accused, Castus Armenta, is obviously guilty. Ana persuades Burilis to withdraw his men by promising a swift investigation. Din interviews the innkeeper, who reveals that the victim, Zansay Burav, and Castus were secret lovers and had been meeting for over a year. Examining the scene, Din finds Zansay brutally killed but with no signs of a struggle or defensive wounds. During the inspection, Din is alarmed by a new “voice” in his head, which Ana explains is a “maturation” of his life-shortening cognitive augmentations. Based on the strange evidence, Ana theorizes that Zansay calmly lay down to die after being grievously wounded and sends Din to ask Castus what Zansay did after she died—an instruction that greatly perplexes Din.

While walking to the Lacanthim jail, Din is overwhelmed by a gloomy melancholy at Ana’s revelation that his augmentations as an engraver have reached maturation: He has reached the peak of his powers, which hereafter will begin a slow, irreversible countdown to the loss of his mental functioning and then to an early death. Din reflects on his choice to undergo the Sublime suffusions—to be augmented with the blood of the leviathans in order to serve the Empire—a trade made to pay off his father’s debts and save his family from poverty. This decision has physically altered him and set his fate. For three years, he has been estranged from his family, receiving only financial notices, including a bill for his father’s burial costs. Harboring a bitter resentment about sacrificing his future, Din chooses not to know whether his family is content. Trying to push aside dread, he resolves to focus on the current investigation, feeling terribly alone while walking through the city.

Din arrives at the jail to find a tense standoff between a crowd of armed Buravs and a single representative of the Armenta clan: Castus Armenta’s uncle, Trikao. Akun Seriv, princeps of the custodi—essentially a local police chief—barely prevents violence. Din uses his authority as an Imperial Iudex to disperse the mob. Trikao reveals that Castus is the last of four siblings; the other three died recently—two by suicide and one in a horse-riding accident—leading to rumors of a family curse. Princeps Seriv explains the feud’s history, an economic rivalry between the Armentas, who control the local cattle industry, and the Buravs, who produce the beans on which the cattle are fed.

Din interviews Castus, who claims he cannot account for his actions. He describes meeting with Zansay in secret, as they had done many times before. Zansay found a flensing knife in her bag and couldn’t explain how it got there. Both then heard a beautiful, unearthly song that transported them into a dream-like state. Zansay gazed out the window, while Castus felt himself mentally transported to his family’s butchering halls, where he had previously been traumatized by the violent work of cattle butchery. When he became aware of his surroundings again, he saw Zansay grievously wounded but strangely serene. He remembers that she calmly lay down in her blood, seeming as if nothing could upset her. His next memory is of being outside covered in her blood. Castus confirms that Zansay’s injuries match the precise cuts he was trained to make with a flensing knife for his family’s business. Overcome with guilt and horror, Castus declares that he wishes to be executed. The chapter ends as Din tells Seriv, the princeps of the local custodi, that they must go to the forest where Castus was found.

Din travels on horseback with Seriv to the forest of Sapirdad, an hour’s ride from Lacanthim. He observes its unnatural appearance: purple-hued trees with pale trunks growing in hexagonal patterns. Seriv explains that the forest was created by the ancient Khanum, possibly to guard the tombs of the Daljen, the first of the old imperial tribes to vanish in the ancient past. The Khanum augmented the trees to grow in unnatural ways intended to ward off intruders. As they approach, the narrator feels an unsettling gloom, which Seriv identifies as a fear-inducing pheromone emitted by the augmented trees, forcing them to dismount their skittish horses and proceed on foot.

Seriv shares local rumors, including the theory that the Daljen were cursed and that this curse has now fallen upon the Armenta family, whose line is also ending; the Armentas believe that the Daljen are their ancestors, though this belief may be only a self-aggrandizing myth. He also reveals there have been sporadic sightings of mysterious flashing lights deep within the impassable woods for the past three years. They arrive at the spot where Castus was found, just a short distance into the dense trees. Seriv confirms what Castus has already told Din: that Castus claimed to have been followed, though no evidence was found. Din notes that Castus told him he went into the forest to pray. Seriv confirms that there are scattered shrines within the forest, but he maintains that Castus was simply “out of his head” (60).

After hearing Din’s account, Ana formulates a theory that both Zansay and Castus were infected with a modified fungus called the guiding web. This fungus, used to condition drokha-cats for farm labor, makes its host highly responsive to specific audio pitches, compelling them to perform associated actions. Ana suggests that a third party used inaudible notes to puppet Castus into committing the murder and Zansay into not resisting; Castus’s work in the flensing halls was the conditioning that led him, under the influence of the web, to kill Zansay in the same manner in which he previously butchered animals. To prove this, she has Din retrieve her collection of musical instruments. As Ana plays a series of high-pitched notes on a shawm, Zansay’s corpse convulses and sighs, confirming that her body is still responsive to the conditioning even after death.

Realizing the gravity of this discovery, Ana sends Din to fetch Princeps Seriv. She explains her theory and provides a horrifying demonstration by making the corpse move again. Seriv is stunned, recognizing that this means the Armenta family’s recent tragedies may have been orchestrated murders, not the result of a curse. The chapter concludes with Seriv’s critical revelation: It was the Burav family—the Armentas’ main rivals—who developed the guiding web fungus, and the individual who pioneered this technology was Zansay’s own father, Burilis Burav, making him the prime suspect.

Ana gathers Din and Seriv at their new quarters—a room at the Green Drover Inn—for a secret meeting. She further explains her theory that the killer is using a new strain of the guiding web fungus to condition multiple human victims who are unaware of their state. She warns that if the killer discovers their investigation, they could trigger a wave of murders and suicides. This revelation horrifies Seriv, who realizes he could also be infected.

To proceed with utmost secrecy, Ana devises a two-part plan. First, she decides against releasing Zansay Burav’s body, instead ordering Seriv to find the Orbiis—the imperial agricultural department. As experts on fungi who are politically neutral, Ana wants them to perform an autopsy on Zansay to analyze the unique neurofungus.

Second, Ana turns her attention to the recent string of deaths in the Armenta family, which she now suspects were murders disguised as suicides and accidents. Seriv reveals that the family matriarch, Velona Armenta, has already been obsessively investigating her children’s deaths, believing them to be divine punishment. Seeing a potential source of information, Ana tasks Din with contacting Velona’s brother, Trikao, to arrange a meeting. Seriv mentions that Trikao is Velona’s older brother, and Din wonders aloud why Velona—and not Trikao—is head of the Armenta clan. Seriv explains that inheritance among the clan is determined by a competition in which all siblings compete to raise the largest herd of cattle. Velona won this competition, making her the leader of the family.

Din goes to a bar called the Crooked Horn to find Trikao Armenta. Trikao is in a somber mood and becomes defensive when asked about the previous deaths in his family, which he attributes to the family’s supposed curse. He angrily tells the Din not to dig into his family’s past suffering. Deciding not to reveal the suspicion that the deaths were orchestrated, Din instead asks to speak with Trikao’s son, Ippeas, and his betrothed. Trikao agrees, stating that the betrothed, a skilled rider, should arrive first. A young woman soon gallops up on a destrier—a huge, augmented horse—displaying such skill that it appears as if horse and rider are one organism. When she dismounts, both she and Din are rendered speechless at the sight of each other. The chapter ends with the revelation that the woman is Din’s long-lost sister, Fotia.