Those Beyond the Wall

In a harsh desert future, the walled metropolis of Wiley City thrives under an artificial atmosphere while the community of Ashtown survives in its shadow, governed by an emperor and policed by leather-clad soldiers called runners. Scales, a runner and mechanic, narrates from within this world of rigid loyalty, ritualized violence, and stories that substitute for truth.

While covering a shift at the House, a combined brothel, counseling center, and community institution run by a gender-nonconforming proprietor named Exlee, Scales watches her friend Helene X die as bones push through her skin from the inside, with no attacker in sight. At an emergency meeting, surveillance footage reveals five simultaneous deaths in Wiley City at the same millisecond, confirming the killings are coordinated. The emperor, Nik Nik, privately sends Scales to check on a scientist named Adam Bosch, betraying a depth of concern she does not yet understand. Mr. Cheeks, Scales's closest friend and superior officer, drives her toward the city wall. Scales reflects on their strained closeness, harboring feelings Cheeks has quietly foreclosed.

Scales finds Adam on a low floor of Wiley City, his body modified with bionic replacements after Ashtown destroyed his multiverse-traversing operation years earlier. Adam identifies the phenomenon as "dop backlash": a lethal reaction triggered when a person encounters their alternate self, or dop, from another universe. He believes someone on a parallel Earth has weaponized this process, killing native versions to make room for incoming travelers. Scales escorts Adam to Ashtown, where he verifies Nik Nik's identity by testing knowledge only someone from this world would possess.

Nik Nik pairs Scales with Mr. Cross, a runner she despises, for an intelligence-gathering mission in Wiley City. Cross is a pale, blue-eyed former Ruralite from the nearby religious community. A witness reveals she saw a ghostly double of one victim before the killing. Scales directs Splice, Ashtown's surveillance specialist, to pull surrounding footage. Enhanced images confirm these doubles and reveal two figures behind them: a version of Adam and the traverser Caramenta, known as Cara, an Ashtown-born woman Adam once employed to walk between worlds. Scales realizes Cross is Cara's brother, from the Ruralite ruling family.

A trip to the Ruralite compound to draw out whoever has been tracking Adam brings Cara and her wife Dell Ikari, who suspects her own father was replaced by a dop after the night of the deaths. A bomb strikes the emperor's vehicle. Nik Nik invokes "Emperor's blood," a protocol mandating the death of anyone who harms his kin. Scales executes one captured attacker; Brand and Rust, the twin runner escorts, kill the other two. Adam then reveals the secret Scales has guarded for years: She is Nik Nik's half-sister. Adam himself is Adranik, the supposedly dead firstborn son of their father, Nik Senior, making the three of them siblings.

At the palace, Cheeks leads Scales to a dungeon cell where a living person with Helene X's face is being held. This version identifies as male and never transitioned as Helene did; he is a dop from the invading world. Adam warns that the next wave of expendable test subjects will be Ashtowners and Ruralites. Scales and Cross return to the city to hunt for imposters but find ransacked apartments and the murdered body of Alden Woods, killed by his wife's dop from the other world. A citizenship scan inadvertently connects Scales to Jeffery Ackerman, a wealthy Wileyite, triggering buried memories of the abusive man who raised her.

Cross, secretly assigned as the wolf, Ashtown's internal investigator, exposes Scales's fabricated backstory by identifying her as Devon Ackerman, Jeffery's adopted daughter. Nik Nik intervenes with a partial truth: Scales is his half-sister. The full history is more violent. At thirteen, Scales's mother brought her to Akeldama, the field of blood, a desert site where people request death. There she discovered the hooded executioner was Nik Senior, her biological father. When Senior began beating Nik Nik, Scales seized a glass-barbed whip and strangled him. Nik Nik protected her, and Exlee took her in, symbolically cutting away her old identity.

Scales discovers that Cross's solitary post has been Akeldama itself, where he has served as Jack Ketch, the executioner, for years, even being forced to kill his own father. On the verge of breaking, Cross confesses he cannot continue. Scales negotiates with Nik Nik: She will accept her role as heir if Cross is permanently removed from executioner duty.

Adam determines that a sacred Ruralite cave contains barsamin, an astronomical element derived from evaporated black holes that can deflect dop backlash. He pushes Scales into a barsamin pool; submerged, she experiences temporal visions of Cross dead by suicide and a future of war. Outside the cave, the second wave of dop backlash strikes: Brand is killed, and a dop of Nik Nik appears at the palace, confirming the cave protected the real emperor.

After Cheeks confesses to his unauthorized relationship with Esther, Cross's twin sister and Ruralite leader, Scales delivers his punishment beating, channeling unspoken love into every blow. Adam negotiates with Wiley City's mayor, offering to infuse barsamin into the city's atmosphere in exchange for admitting Ashtowners inside the walls. Cara discovers Adam has hidden evidence of an earlier, undetected crossing. Scales, Cara, and Cheeks infiltrate the city for footage suggesting the vice mayor is a dop. When enforcement closes in, Cheeks runs out as a decoy to protect Scales.

Scales repeatedly submerges in the barsamin pool, experiencing hundreds of possible futures. In every scenario, Ashtown is destroyed, except those where Cheeks's death becomes a martyrdom story that restrains the coalition of cities from retaliating. When Cheeks is returned alive but severely beaten, Scales visits him in the infirmary. Using the emperor's truth-serum ring, she asks him to say "I'm in love with you." The lie, combined with serum already in his system, triggers a fatal reaction. Cara witnesses the act, severing their relationship.

After Scales's coronation, Splice releases staged footage of Cheeks surrounded by enforcement's black-jumpsuit squad as he holds up his hands and announces his day pass. The footage goes viral, shifting public opinion against the mayor. Scales leads the runners to the city wall, where the ensuing battle serves as a distraction: While runners and Wileyite allies engage enforcement, Scales slips into tunnels and detonates pre-laid explosives, collapsing an entire section of the wall. The barsamin-infused atmosphere radiates outward across the desert, providing shade and agricultural potential to Ashtown for the first time.

In the atmospheric infusion room, Nik Nik kills the mayor and reshapes her body to resemble dop backlash, installing the vice mayor, herself a dop from the first crossing, as a reform-minded replacement. When spectral doubles of Adam and Cara appear, Adam accepts that the infusion cannot protect him. His joints break from backlash, and Nik Nik shoots him as a mercy. Cara braces for death, but the atmosphere completes its protection just in time: The other-world Cara dies instead.

At Adam's funeral, Cross performs a Ruralite burial ceremony. Scales and Cross acknowledge their feelings, kissing for the first time. Scales arranges for Esther to find a surviving dop of Cheeks outside the city. In the novel's final image, Scales recalls a barsamin vision from a world where she, Cheeks, and Cross grew up as children. A bright day, an extreme solar event, forces them inside, and the three stand at a window. Cheeks puts an arm around each of them and says, "Watch. This is the best part."