Kai stood frozen before the monolithic doors of the gravity elevator. The indicator panel showed the car locked on the 140th tier, only just beginning its slow descent. Travel time: forty minutes.

  Maya didn't have forty minutes. She didn't even have forty seconds. The black tendril, gorged on the active symbiont of the Abyss, had already closed to strike range in her bedroom.

  Kai spun away, cutting off the useless thought of the elevator. His gaze locked onto the central node of the Substrate in the middle of the bunker—a pulsating crimson mass resembling the exposed heart of some colossal beast. A biological impulse couldn't outrun data transmission through the Consortium’s fiber optics, but Kai was part of the network itself. He and Avelo shared a single nervous system, divided only by miles of concrete and magnetic fields.

  Kai lunged toward the node. On the run, he whipped out a ceramic blade and, without slowing, slashed the veins on both palms. Sharp pain flared through his forearms as hot blood surged over his pale skin. The boy who had once hidden in the ventilation shafts was gone, dissolved into the past. Before the living "heart" of the Abyss stood a predator defending its territory.

  With a violent shove, Kai plunged his bloodied hands deep into the pulsating mass of the Substrate.

  The shockwave of a foreign consciousness nearly stopped his own heart. It was like trying to wrestle control of a runaway locomotive with bare hands. A white flash exploded behind his eyes; a high-frequency shriek tore through his ears. Kai collapsed to his knees but didn't break contact, allowing his blood—the carrier of the ultimate biological code—to fuse with the black matter.

  He forced his mind to transmit upward through the City’s arteries. He tore through foundations and pierced the shielding of the Middle Tiers, ignoring the nausea and the micro-ruptures of capillaries in his own brain. He searched for that specific thread. The single capillary Avelo had extended into Maya’s sterile bedroom through a single drop of his own blood.

  In the Upper Tiers, an absolute, artificial silence reigned.

  Maya slept the heavy sleep of a person exhausted by a forty-eight-hour shift. She heard nothing. But when an ice-cold drop hit her collarbone, her eyes snapped open. An Architect’s instinct moved faster than panic. The room smelled of wet earth and scorched copper—physiological markers of the Abyss that had no business being at this altitude.

  Maya slowly turned her head. Hovering directly above her, rising from the nightstand, was a glossy-black tendril. The lethal lash pulsated, studying the rhythm of her carotid artery.

  The tendril jerked downward. Maya instinctively squeezed her eyes shut, braced for the impact.

  Instead of pain, there was a wet, crunching sound of tearing organics. She opened her eyes. The black lash was frozen an inch from her face. It was twisting and buckling from within. A fierce violet glow was rupturing through the black skin.

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  The Substrate was at war with itself. A second thread—thin, dazzlingly violet—had erupted from the same napkin and locked the black growth in a death grip, wrenching it aside. In the flickers of violet light, Maya caught a momentary glimpse of a human face distorted in agony. Kai’s face.

  The violet thread made a sharp, snapping lunge. The black tendril burst soundlessly, scattering onto the blanket as a handful of gray ash. The remains of the Substrate instantly retracted back into the napkin’s structure, leaving behind only the sharp tang of static.

  An eternity later, the bedroom doors hissed open. Kai stood on the threshold.

  His suit was in tatters, his tie gone. His face was the color of chalk; blood leaked slowly from his nostrils and ears. His palms, wrapped in strips of his shirt, were soaked crimson. He leaned heavily against the frame, struggling to focus his glassy eyes.

  Maya hadn't called security. She was waiting. Beside her stood an open medical kit and a vial containing the ash.

  "You saved me," she said quietly, carefully taking his mutilated hands. "Come in. You’re showing signs of critical synaptic shock."

  Kai allowed himself to be guided into a chair. He watched the girl’s precise, professional movements. "You didn’t call Internal Security," he rasped.

  "If I had called Thorne, they would have realized this ash is a living structure. They would have realized you aren't just an engineer, Kai. You are part of this system. And it obeys you. At least when you are willing to pay with yourself."

  Maya looked up. There was no fear in her eyes, only the cold intellect of a researcher. "The thing that attacked me... it was trying to remove a threat. I got too close to the Obelisk. And the thing that saved me, tearing its own flesh... that was you."

  Kai leaned his head back against the chair. "His name is Avelo," he exhaled. "My brother. A symbiont. Fourteen years ago, he became the mind of the Abyss. He wants to bring down the Obelisk. That needle is the only thing keeping Him under sedation. If the foundation collapses, millions of people become fertilizer."

  "But you stopped him," Maya squeezed his hand. "Today you proved you can seize control. We will save the City, Kai."

  Kai gave a twisted grin. He looked at this idealist who still believed in the power of blueprints. In that moment, the voice spoke in his skull again. The link was restored, but Avelo wasn't screaming. His whisper was dry and mathematically calculated.

  "You stole my food, brother," the Substrate hissed. "You broke the balance of the Garden for the sake of a single weed. My roots have withered in this battle. They need energy. Give me an equivalent, or I will collapse the Obelisk’s eastern support right now."

  Kai turned pale. The eastern support held the entire industrial sector of the Middle Tiers. Tens of thousands of jobs. Thousands of lives.

  "What’s happening?" Maya noticed his face go dead.

  Kai didn't answer. He slowly activated his communicator. A map of the Lower Sector unfolded on the screen. "A thousand lives for one," Avelo dictated. "Pick a flowerbed, Gardener."

  Kai’s finger hovered over the sensor. He looked at Maya. She was alive only because he had broken the rules. And the rules of the Abyss always carried a price.

  "Kai, what are you doing?" panic sharpened the girl’s voice.

  Kai hit the call button. The face of the Sector’s security chief appeared on the screen. "Block Four," Kai’s voice sounded like a cold mechanical synthesizer. "Seal all external pressure doors. Cut the filtration. Terminate oxygen supply."

  The officer on the screen turned deathly pale. "Director... there are three thousand civilians in Block Four. Hydroponic hubs, residential cells..."

  "Execute the order," Kai cut him off. "And open the technical floor hatches. All of them. Every waste chute."

  He broke the connection. Maya recoiled, pressing her palms to her lips. In her eyes, Kai was no longer a savior. Sitting in her bedroom chair was the most terrifying monster this city had ever spawned.

  Kai rose slowly. Somewhere deep below, under miles of concrete, three thousand people began to suffocate to feed the roots of the Garden. The balance was restored.