A Trade of Blood (2026) is a fantasy mystery novel by Robert Jackson Bennett. The novel is the third installment in the Ana and Din Mysteries series, which begins with The Tainted Cup (2024), which won the Hugo and World Fantasy awards. Bennett is a celebrated author of speculative fiction, known for his critically acclaimed Divine Cities and Founders trilogies, which have been nominated for Hugo, World Fantasy, and Locus awards.

Set in the biologically augmented Empire of Khanum, the novel follows imperial investigators Dinios “Din” Kol and Ana Dolabra as they are dispatched to the remote canton of Sapirdad to solve the murder of a high-status young woman. The case threatens to ignite a clan war between two powerful families who dominate the region’s lucrative but brutal cattle industry. As Din and Ana uncover a conspiracy involving a mind-controlling neuro-fungus, their investigation forces them to confront the society’s deepest corruptions. The novel uses its mystery plot to explore themes such as The Moral Cost of Meat Production, Class Hierarchy as a System of Exploitation, and The Destructive Pursuit of Family Legacy.

This guide refers to the 2026 Del Rey edition.

Content Warning: The source text and this guide contain depictions of graphic violence, death, death by suicide, substance use, cursing, animal cruelty and death, and mental illness.

Plot Summary

Dinios “Din” Kol, an investigator with the Imperial Iudex (the government body responsible for investigating crimes against the Empire), and his reclusive, brilliant superior, Immunis Ana Dolabra, are dispatched to the city of Lacanthim to investigate the murder of Zansay Burav. Din is an engraver, meaning that his mind has been augmented to possess perfect recall. He carries vials of various scents with him as he investigates, sniffing these to embed and later recall his memories. The case is politically volatile, as the victim is from the Burav gentryclan (one of the two powerful, landowning families of the region) and the accused, Castus Armenta, is from the rival Armenta gentryclan, pushing the two powerful cattle-industry families to the brink of war. Upon arriving, they find the city in an armed standoff. Zansay’s father, Burilis Burav, demands the swift conviction of Castus and the return of his daughter’s body. At the crime scene in the Cat’s Eye Inn, Ana and Din learn from the innkeeper, Ithia, that Zansay and Castus were secret lovers who had been meeting there for over a year. The scene itself is perplexing: Zansay has been butchered with a flensing knife, a tool for processing cattle, yet there are no signs of a struggle. Ana deduces from strange bloodstains that Zansay calmly lay down in her own blood after being mortally wounded. During the investigation, Din is troubled by a new maturation of his abilities, wherein his memories seem to possess a voice that points out inconsistencies, making him fear for his long-term mental well-being, as he is aware that all engravers eventually succumb to dementia-like symptoms.

Din interviews Castus, who is distraught and confused. He claims to remember a beautiful song outside the inn room, followed by a dreamlike trance where he experienced the sights and smells of the flensing halls where he is forced to work. When the vision faded, Zansay was mortally wounded, and he saw her lie down before he panicked and fled into the nearby ancient forest, hoping to pray before a statue of a revered figure from the ancient past—Master Gaddar. Suspecting a form of mind control, Ana tests a radical theory. She plays a series of high-pitched notes on a wind instrument called a shawm. Though it takes her some time to find the right pitch, the sound eventually causes Zansay’s corpse to twitch and sigh. This confirms her hypothesis: both victim and killer were under the influence of the “guiding web,” a neuro-fungus developed by Burilis Burav himself to condition small, furred creatures called drokha-cats to harvest crops. Though this fungus is not known to affect humans, Ana theorizes that someone must have found a way to alter it to do so. They enlist the help of the local custodi commander (police chief), Princeps Atun Seriv, and the eccentric head of the Imperial Orbiis (the agricultural department), Commander Raudoti Tauri, who agrees to perform an autopsy before the fungus can cause the corpse’s head to “fruit” and reveal its presence. The investigation is further complicated when Din is shocked to reunite with his long-lost sister, Fotia, who is now a top drover for the Armentas and betrothed to Ippeas Armenta, Castus’s cousin.

Fotia and Ippeas help Din and Ana gain an audience with the Armenta clan matriarch, Velona, who is grieving the recent deaths of her other three children: the suicides of Lyimo and Sagma, and the accidental death of Gevma. Velona, who is undergoing dangerous fertility treatments to produce a new heir, believes her family is under a divine curse from the ancient Daljen people—ancestors now worshipped as gods, one of whom is the Master Gaddar to whom Castus tried to pray. She reveals that both Sagma and Gevma suffered from nightmares of being trapped and paralyzed in their rooms just before their deaths—a key symptom of the guiding web’s influence. The case takes a dark turn when the entire Burav estate burns to the ground while Ana and Din are en route to confront Burilis. The entire Burav clan perishes, except for Zansay’s brother, Jalin, who is critically injured after leaping from a window. A witness describes seeing a “prowler,” resembling an Armenta field hand, near the estate before the fire, and another survivor reveals that the Buravs were frozen in place as the fire raged, whispering as if screaming in a dream. Ana correctly deduces that the prowler was Ippeas, lured into a trap by a letter promising to exonerate Castus. Ippeas is arrested for his own safety, and a test confirms that he too is infected with the web.

When Castus is triggered by a specific tune played on a pipe near the jail, the fungus erupts from his head in a horrific “fruiting,” transforming him into a zombie-like killer compelled to reenact his conditioned behavior of butchering. Din is forced to fight and behead him. Ana persuades Castus’s uncle, Trikao Armenta, to allow the exhumation of the other dead Armenta children. Their tombs reveal that Sagma and Gevma’s bodies have also fruited. Lyimo’s body shows only a small growth, suggesting that the killer’s method was less refined during this first murder. On Lyimo’s back, Din discovers a bruise and a small cut perfectly matching the pointed hawk’s-beak tughra ring that only Jalin Burav is known to wear. As they connect him to the first murder, Jalin escapes his medical ward and flees into the altered forest. In the ruins of the Burav estate, Ana opens a hidden vault belonging to Burilis and finds his research journal on the web, a cache of tools for entering the forest, and his drunk but living housekeeper, Madi Istelia. Istelia reveals Jalin’s deep hatred for his family’s trade and his torment at the hands of Lyimo. She also states that Jalin once lamented, “My soul is not my own anymore. He owns me utterly” (282), suggesting that someone else manipulated Jalin to commit violent acts.

Ana pieces together the timeline: Jalin, a tormented and angry young man, used his father’s research to murder Lyimo. He was then discovered and blackmailed by a second, more cunning killer who used him as an accomplice. This mastermind then orchestrated the precise, varied deaths of Sagma and Gevma to eliminate Velona’s heirs. Jalin was forced to play the pipe that triggered the murder of his own sister, Zansay, a crime designed to frame Castus. When the Iudex’s arrival delayed the return of Zansay’s body, Jalin panicked, knowing the fruiting would expose the web and implicate his family. He set fire to his own home, killing his clan in a final, desperate act. Din and Tauri travel to the forest to seek out Jalin. On the way, they pass the flensing halls where cattle are butchered, and the sight overwhelms and saddens Tauri, who explains to Din that his role as commander of the Orbiis makes him uniquely sensitive to the health of the landscape. The violence and ecological destruction wrought by the flensing halls causes him great emotional distress. Din and Tauri bond over the emotional toll their work takes on both of them, and a mutual romantic attraction begins to bloom. In the forest, Din and Tauri find Jalin dead by suicide. They also discover Burilis’s hidden laboratory and his journal, which details the web’s development but makes no mention of its use on humans. Fotia, meanwhile, learns from a former drover that Sagma was found hanged not with a rope, but with a decorative ribbon.

Ana realizes this is the final clue. Sagma’s conditioned nightmare was of repeatedly dressing herself, an act that culminated each morning in tying a ribbon around her neck. Only someone intimately familiar with her habits—and who gifted her those very ribbons—could have arranged such a death: Trikao Armenta. Ana sets a trap, luring Trikao to the Green Drover tavern by sending a letter to Velona claiming to possess damning evidence. Trikao uses a decoy to distract the custodi, then enters the tavern and plays his pipe, paralyzing the infected patrons, including Din and Ana. However, Din’s engraver augmentations allow him to partially resist the paralysis, while Ana reveals her immunity by ambushing the shocked Trikao with a painful, nonlethal lypi lance. She reveals his entire plot: Angry at being cut off from inheritance after losing a contest to Velona in his youth, Trikao orchestrated the deaths of Velona’s children so that his own son, Ippeas, would become the sole heir to the vast Armenta fortune.

In the aftermath, a horrified Ippeas decides to break up the Armenta estate. Ana admits her immunity stems from her unrevealed Khanum heritage. The mystery of the web’s origin remains until Din and Tauri follow Burilis Burav’s trail to the “cup of heaven,” a sealed site deep in the forest. Inside, they find a vast subterranean lake where ancient, fungus-crowned undead beings eternally stir waters filled with human bones. This is the true source of the web, revealing a horrific secret: The ancient Daljen tribe perfected the fungus to enslave the ancestors of the Empire’s common folk. The emperor’s Daavir tribe committed genocide to stop them and sealed the site, erasing the crime from history. The revelation shatters Tauri, who realizes Ana’s true nature as a descendent of the Daljen and breaks off his budding relationship with Din. The investigation concludes, leaving Din to grapple with the rot at the foundation of the Empire and the implications of his superior’s true identity.