Our Dark Duet (monsters of Verity, #2)

The second and final installment in the Monsters of Verity series picks up six months after the events of This Savage Song. In this world, human violence gives rise to literal monsters: Corsai, creatures of shadow that feed on flesh; Malchai, vampiric beings born from murder; and Sunai, rare entities born from mass tragedy that can reap the souls of sinners through music. The city of Verity, divided by a fortified barricade called the Seam into North and South, is at war. Callum Harker, the former ruler of North City, is dead, and Sloan, the Malchai born from Harker's own crimes, has seized control of the north.

A prelude reveals two rebirths. A new Malchai emerged from a house in the Waste, the lawless stretch of land beyond the city, where Callum's daughter Kate Harker killed a stranger. This monster, who calls herself Alice, found Sloan dying with a steel bar through his back and pulled it free. Both know their creators: Sloan's maker, Callum, is dead; Alice's maker, Kate, is not.

Six months later, Kate lives under an alias in Prosperity, the wealthy neighboring territory, hunting monsters with the Wardens, a group of hacktivist college students. She carries the guilt of the stranger's death, which stained her soul red, and searches every night for news from Verity, but the territory's communications are completely dead.

In Verity, August Flynn serves as captain of the Flynn Task Force (FTF) Night Squad, screening refugees by playing his steel violin, which forces souls to the surface: white for the innocent, red for sinners. He is haunted by the voice of his dead brother, Leo, who urges him to abandon his desire to be human and embrace his nature as a weapon. August's older sister, Ilsa, the first Sunai, has lost her voice after Sloan cut her vocal cords. A new Sunai named Soro, who identifies neither as male nor female but simply as a Sunai, believes their sole purpose is destroying monsters and reaping sinners. Henry Flynn, August's adoptive father and head of the FTF, is visibly ill, growing gaunt and coughing, though neither he nor August will acknowledge it. The FTF Council is divided over whether to defend South City alone or attempt rescues across the Seam.

Sloan rules from Harker Hall's penthouse, obsessed with killing Kate. Alice lives with him, raiding FTF weapons caches and deafening Malchai by driving hot metal into their ears so they will be immune to Sunai music. Alice sets a trap using Fangs, humans who wear steel collars and serve the Malchai. August's partner, Rez, a sniper, is killed in the ambush. August reaps the Fangs in a rage, his darker nature surfacing, and returns to the Compound soaked in blood, embracing the fear he inspires.

In Prosperity, Kate witnesses a restaurant massacre. A man calmly stabs 12 people while a featureless shadow with silver mirror eyes watches and grows more solid with every act of violence. Kate chases the shadow into an alley, where it touches her. She falls into a dark void and is pulled back only by a voice over her earpiece. The encounter leaves a silver shard in her left eye. Violent urges begin pressing against her thoughts, and the shard allows her to see through the creature's perspective. She discovers it is heading to Verity, drawn to the city's potential for violence. Believing she showed it the way through her own dark memories, Kate drives toward the Verity border.

Her journey is harrowing. Her car breaks down, she survives a night besieged by Corsai, and she is chased by Fangs before crashing through the Seam into South City. Soro nearly kills her before August intervenes. Interrogated at the Compound, Kate describes the creature as a shadow that feeds on violence, amplifies dark impulses, and turns humans into killers. August and Ilsa watch the surveillance feed and notice a camera flare when Kate glances at the lens, the same visual distortion cameras produce around monsters, revealing something inhuman in her. They silently agree not to expose her. Alone, August uses his Sunai influence to force the full truth from Kate. She punches him for the violation, then names the creature: the Chaos Eater.

Kate trains with the FTF and, at night, hunts the Chaos Eater with August, using the shard to track it. They arrive too late to prevent another squad from turning their weapons on one another. Kate challenges August about the cold persona he has adopted, insisting the person who wanted to be human is still inside him. They kiss; Kate's red-stained soul surfaces on her skin, nearly causing August to reap her. They pull apart, shaken. Kate confesses she is scared.

Sloan's captive engineer discovers old subway tunnels beneath the Compound, and Sloan shifts his plan to breaching it from below. He lures the Chaos Eater by whipping gathered Fangs into a frenzy; when the shadow appears, Alice drops a gold-veiled cage over it. Gold acts as a prison for monsters.

When Soro discovers the silver spreading across Kate's eyes, she is locked in a cell. Sloan launches a coordinated attack: Alice assaults the Compound's power grid while explosions from the tunnels collapse the surrounding streets. Kate escapes when the power fails and joins the fight, encountering Alice, her own monstrous reflection, face-to-face for the first time.

Sloan broadcasts Henry on every FTF screen, bound with a collar and a countdown timer. The image unites the divided task force. The Night Squads storm the tower but find it nearly empty; Henry has a fake bomb. Alice offers a deal: Kate stays, everyone else goes free. Kate agrees, telling August to return to the Compound.

While the squads are at the tower, Sloan enters the Compound through the tunnels and releases the Chaos Eater, infecting thousands and turning them against one another. Soro plays their flute through the intercom, subduing the infected. August and Ilsa fight Sloan in the lobby; August drives his steel bow through Sloan's heart.

The fully corporeal Chaos Eater stands in the lobby. Ilsa transforms into her true Sunai form, a figure with curved horns and burning wings, and throws her arms around the creature. The collision destroys the Chaos Eater but kills Ilsa, who shatters into dust.

In the penthouse, Kate deliberately releases the Chaos Eater's influence in her mind, gaining the cold focus to match Alice's speed. When Ilsa destroys the Chaos Eater, the shadow vanishes from Kate's mind. She feigns surrender, then drives an iron spike into Alice's heart; in the same instant, Alice drives her hand into Kate's chest.

August finds Kate mortally wounded. She asks if the souls he takes stay with him. He does not know but hopes they do. Kate's soul flows through him, bright and strong, and she dies in his arms.

Three days later, August mourns Ilsa and Kate. His cat, Allegro, returns to him, no longer afraid, a sign that he has reclaimed some of his humanity. Henry survives, though weakened, and the FTF holds a memorial for 298 dead. Soro asks how they should judge soldiers whose souls were stained by acts committed under the Chaos Eater's influence; August suggests that perhaps they are not meant to. He stands on the Compound roof at dusk, lifts his violin, and prepares to continue protecting Verity, holding on to Kate's belief that the pain is worth it if he never lets go.