Chapter 22
title: "What Grows in the Dark" wordCount: 2951
The scalpel is duller than Cass expected, and Eli doesn't scream—he just grips the table edge hard enough that his fingernails crack.
She cuts shallow. The blade parts skin that feels wrong under her hands, too thick, like cutting through leather that's been left in water. Blood wells up dark and slow, almost syrupy. Eli's breathing goes ragged but he doesn't pull away.
"Deeper," he says.
"I'm trying not to—"
"There's nothing left to damage." His eyes find hers. "The override code first. Three inches below the collarbone, left side."
Cass shifts the blade. Behind her, something crashes—Finn upending a storage cabinet, glass shattering across concrete. The yellow gas has reached the far wall now, spreading like spilled paint across the chamber floor. She can hear it hissing, a sound like static between radio stations.
The scalpel finds the subcutaneous chip on the second try. It's smaller than she expected, barely the size of a grain of rice, embedded in scar tissue that suggests it's been there for years. She works it free with the blade tip and drops it into her palm. The metal is warm.
"Pocket," Eli says. "Don't lose it."
She tucks it away. Her hands are shaking now, blood making the scalpel grip slippery.
"Now the lung sample." Eli guides her hand to his left side, between the fourth and fifth ribs. "You'll feel resistance. Push through it."
"This is going to—"
"I know."
Cass positions the blade. Eli's hand covers hers, steadying it, and for a moment she's twelve again and he's teaching her to gut a fish they pulled from the reservoir, his hands over hers showing her where to cut, how to angle the blade so it doesn't catch on bone.
She pushes.
The scalpel slides between ribs and Eli's whole body goes rigid. His other hand finds the dog tags around her neck, grips them hard enough that the chain cuts into her skin. She can feel his pulse through the metal, too fast, too weak.
"There," he gasps. "You feel it?"
She does. Something hard and round, nestled against tissue that shouldn't exist inside a human body. She works her fingers around it, trying not to think about what she's touching, what she's doing to her brother. The mass comes free with a wet sound that makes her stomach turn.
It's not a walnut. It's bigger, the size of a plum, and it's not entirely fungal. There are striations of what looks like muscle tissue, veins that pulse with bioluminescence. The surface is warm and slightly yielding, like touching a tumor that's still alive.
"Jesus," Cass whispers.
"Bag it." Eli's voice is fading. "Finn has sample containers in his pack."
Behind them, Finn shouts something she doesn't catch. There's a whoosh of ignition, then heat washing across her back. She turns her head just enough to see him wielding a makeshift flamethrower—a spray bottle connected to a butane torch with electrical tape and desperation. The entities recoil from the flame, but they're not burning. They're just backing away, regrouping.
"Finn!" She keeps pressure on Eli's side with one hand, holds the sample in the other. "I need a container!"
He's already moving, pack sliding off his shoulder as he maintains the flame barrier with one hand. He tosses the pack and it skids across the floor, stopping just within reach. Cass grabs it, finds a sealed specimen jar, drops the sample inside. The bioluminescence pulses once, twice, then goes dark.
"Coordinates," Eli says. His voice is barely audible now. "Write them down."
"I don't have—"
"Memorize them." He rattles off a string of numbers, latitude and longitude, six different locations. Cass repeats them back, burning them into her memory the way he taught her to remember supply cache locations when they were kids. Each set of coordinates is followed by a designation: Site Gamma, Site Epsilon, Site Theta.
"What are they?"
"Other experiments." Eli's breathing is shallow now, each word an effort. "Places where they tried the same thing. Growing hybrids. Testing immunity protocols."
"How do you know—"
"They showed me. In my head." His hand finds hers again. "They wanted me to understand what I was part of. What they were building."
The gas is ten feet away now. Finn's flame barrier is holding but the entities are adapting, spreading out, looking for gaps. One of them moves differently than the others—taller, its fungal growth more organized, almost architectural. It steps through the flame and doesn't recoil.
"Finn," Cass says. "We have a problem."
He sees it. Adjusts the mixture, adds something from a bottle labeled with chemical symbols she doesn't recognize. The new flame burns blue-white and the entity stops, actually stops, its body rippling like water disturbed by a stone.
"Phosphoric compounds," Finn says. "It's not the heat—it's the phosphorus."
The entity retreats. The others follow, maintaining distance from the new flame. But there are more of them now, emerging from the shadows at the chamber's edges. Too many to hold off with one improvised torch.
"Airlock," Eli says. "Thirty seconds."
Cass looks at him. At what's left of him. The fungal growth has spread across his chest now, creeping up his neck in delicate tendrils that pulse with that same bioluminescent glow. His eyes are still his own but they're dimming, the light behind them fading like a candle burning down to nothing.
"Come with us," she says.
"Can't." He tries to smile. Fails. "I'm the lock on the door. Soon as I let go, they'll follow you."
"Then don't let go. We'll figure something else out."
"There is nothing else." His hand tightens on hers one last time. "Mom doesn't know I'm alive. Keep it that way."
The words hit her like a blade between the ribs. She opens her mouth to argue, to tell him that's not fair, that their mother deserves to know, but Eli's already shaking his head.
"She buried me once. Don't make her do it twice."
"Eli—"
"Promise me."
Cass looks at her brother and sees the kid who took the blame when she broke into the supply depot, who gave her his ration cards when she was sick, who taught her that survival meant making the hard choices before they made you. She sees all of that and she sees what he's become, what he's choosing to be in this moment.
"I promise," she says.
Eli nods. Lets go of her hand. "Airlock. Now."
The airlock is a steel cylinder barely wide enough for two people, with a manual wheel lock on each end and a control panel that flickers with dying power. Cass hits the inner door release and it grinds open, hydraulics screaming. Finn backs toward it, still maintaining the flame barrier, the entities pressing closer now that they sense escape.
"Go," he says.
Cass doesn't move. She's watching Eli drag himself toward the chamber control panel, leaving a trail of dark blood and something else, something that glows faintly in the dim light. He's not walking anymore. He's crawling, pulling himself forward with his arms while his legs drag uselessly behind him.
"Cass." Finn's voice is sharp. "We have to go."
She knows. She knows and she still can't move, can't look away from her brother hauling himself across the floor like a broken thing, like something that should have died already but refuses to stop. The entities are circling now, staying just outside the flame's reach, and she realizes they're not attacking because they're waiting. Waiting for Eli to reach the panel. Waiting to see what he'll do.
He reaches it. Pulls himself up using the console edge, fingers finding the controls with muscle memory that survives even as his body fails. The screen flickers to life, showing the chamber layout, the gas distribution system, the sterilization protocol waiting to be activated.
"Thirty seconds," Eli says again. His voice comes through the intercom now, tinny and distant. "Get in the airlock."
Cass steps backward. Her heel crosses the threshold and the motion sensor chimes, a pleasant sound completely at odds with everything happening. Finn follows, the flame dying as he releases the trigger, and the entities surge forward.
Eli hits the button.
The inner door slams shut with a sound like a gunshot. Through the small window, Cass sees the chamber flood with yellow gas, sees the entities dissolve like sugar in water, sees her brother standing at the console with his hand still on the activation switch. He's looking at her through the window and his mouth is moving, forming words she can't hear through the steel and the gas and the distance between them.
The intercom crackles. "Tell her I fixed it. She'll understand."
Then the gas reaches him and Cass turns away because she can't watch, won't watch, refuses to see what happens when the sterilization protocol does what it's designed to do. Finn's hand finds her shoulder and she shrugs it off, focusing on the outer door controls, on the wheel lock that needs to be turned exactly three full rotations counterclockwise to release.
She turns it. Once. Twice. Three times.
The outer door opens onto an emergency access tunnel, narrow and dark, with emergency lighting that casts everything in shades of red. The air smells like rust and old water and something chemical she can't identify. Behind them, the inner door is sealed, the chamber beyond it silent.
Cass steps into the tunnel. Doesn't look back.
The tunnel runs for what feels like miles but is probably only a few hundred yards, sloping upward at a gentle angle that makes her calves burn. The emergency lights are spaced every twenty feet, creating pools of red illumination separated by stretches of darkness that feel absolute. Finn follows close enough that she can hear his breathing, ragged and uneven, but he doesn't speak and neither does she.
She's still carrying the specimen jar. She can feel it in her pocket, warm against her thigh, pulsing with a rhythm that might be her imagination or might be something worse. The override code chip is in her other pocket, a small hard point of pressure that reminds her with every step that she cut it out of her brother's chest while he was still alive.
The tunnel ends at a maintenance junction, a small room with pipes running across the ceiling and a ladder leading up to a hatch. Finn stops at the ladder base, finally breaking the silence.
"We need to examine the sample."
"Not here."
"We don't know how long it stays viable. If the tissue degrades—"
"I said not here." Cass keeps moving, checking the junction's other exits. Three tunnels branch off in different directions, each one marked with faded paint and designation codes she doesn't recognize.
Finn doesn't follow. She hears him unzipping his pack, the clink of equipment being arranged. When she turns back, he's set up a portable work light and spread a tarp across the floor, creating an improvised examination space that would be almost professional if it wasn't happening in a maintenance tunnel under a facility that just killed her brother.
"Cass." He's not looking at her. He's looking at the specimen jar, holding it up to the light. "This shouldn't exist."
"I know."
"No, I mean it literally shouldn't exist. The fungal structure and the human tissue—they're not just coexisting, they're integrated. Sharing cellular walls. This isn't infection, it's hybridization."
Cass moves closer despite herself. In the work light, the sample looks different than it did in the chamber. The striations she thought were muscle tissue are actually something else, something that looks almost like circuitry, branching patterns that connect the fungal growth to the human cells in a network too organized to be natural.
"The source isn't just infecting people," Finn says. His voice has that quality it gets when he's working through a problem, fast and focused. "It's building something. Using human biology as a framework."
"For what?"
"I don't know. But look at this." He points to a section where the fungal growth forms a dense cluster. "This is neural tissue. Or something that mimics it. The fungus is creating structures that can process information, store memory."
Cass stares at the sample. At the thing that grew inside her brother's body while he was still alive, still conscious, still himself. She thinks about what Eli said—that the entities showed him things, made him understand. She thinks about the coordinates he gave her, the other sites where they tried the same experiments.
"How many people?" she asks.
"What?"
"How many people did they do this to? How many test subjects are out there right now with these things growing inside them?"
Finn doesn't answer. He's looking at the sample with an expression she can't read, something between fascination and horror. His hands are steady as he takes measurements, records observations in a notebook pulled from his pack, but she can see the tension in his shoulders, the way he's holding himself too carefully, like he's afraid of what he might do if he relaxes.
"The immunity research," he says finally. "The trials Vera authorized. What if they weren't trying to create immunity? What if they were trying to create this?"
The words hang in the air between them. Cass feels something cold settle in her chest, a weight that has nothing to do with grief and everything to do with understanding. She thinks about the Council's secrecy, about Vera's careful control of information, about the way Deep 9 was sealed off and forgotten.
"They knew," she says.
"They had to. You don't accidentally create something like this. This is deliberate. Controlled."
"Then why keep it secret? If they can control the infection—"
"Can they?" Finn looks at her now, and there's something in his eyes she hasn't seen before. Fear, maybe, or something close to it. "Because from where I'm standing, it looks like the infection is controlling them."
A sound echoes down one of the tunnels. Distant but distinct—footsteps, multiple sets, moving fast. Finn kills the work light and they're plunged into darkness broken only by the emergency lighting's red glow. Cass's hand finds the knife at her belt, the one she used to cut into Eli's chest, still sticky with his blood.
The footsteps get closer. Voices now, low and urgent, using tactical hand signals she can't see but can imagine. Security teams move a certain way, with a rhythm that's unmistakable once you've learned to recognize it.
"They found us," Finn whispers.
Cass doesn't answer. She's already moving, grabbing the specimen jar and shoving it back in her pocket, helping Finn pack up the equipment with movements made efficient by necessity. They have maybe thirty seconds before the security team reaches the junction. Maybe less.
The ladder. It's their only option. Cass hits the rungs first, climbing fast, her hands finding purchase on metal worn smooth by decades of use. Above her, the hatch is sealed with a wheel lock identical to the one on the airlock. She spins it, feeling the mechanism resist, then give.
The hatch opens onto a maintenance corridor, wider than the tunnel, with actual lighting and air that doesn't taste like rust. Cass pulls herself through and reaches back to help Finn up. Below them, the footsteps reach the junction, voices calling out coordinates and clearance codes.
They run.
The corridor branches and branches again, a maze of passages that all look identical in the fluorescent lighting. Cass picks directions at random, trusting instinct over logic, taking turns that feel right even when they don't make sense. Behind them, the pursuit continues, but the sounds are getting more distant, confused by the corridor's acoustics.
They round a corner and stop.
Soren Latch is waiting with a security team, six people in tactical gear with weapons drawn but pointed at the ground. He's standing in front of them, hands visible and empty, his expression carefully neutral. When he sees Cass and Finn, something flickers across his face—relief, maybe, or calculation.
"My mother knows you're out," he says. His voice is quiet, controlled, nothing like Vera's measured formality. "I'm here to help you disappear before she finds you."
Cass's hand tightens on the knife. Behind Soren, the security team shifts, weapons still down but ready to move. She can see the calculation in their eyes, the way they're assessing threats and exits, waiting for orders.
"Why would you do that?" Finn asks.
Soren's eyes don't leave Cass. "Because I know what she did to your brother. What she's been doing in Deep 9 for the last three years. And I know what you're carrying in your pocket."
The specimen jar feels suddenly heavy, burning against her thigh. Cass doesn't move, doesn't speak, just watches Soren and tries to read the truth in his face. He looks like his mother—same sharp features, same careful control—but there's something else there too, something that might be genuine or might be the best performance she's ever seen.
"You have about two minutes before her team reaches this corridor," Soren says. "After that, I can't help you. So you need to decide right now if you trust me."
Behind them, the sound of pursuit grows louder. Voices calling coordinates, boots on concrete, the mechanical click of weapons being readied. Cass looks at Finn and sees her own uncertainty reflected back at her. They're trapped between Vera's team and Soren's, between certain capture and possible betrayal.
Soren takes a step forward, hands still visible, still empty. "I'm not my mother," he says. "And I'm not going to let her bury this the way she buried everything else."
His hand extends, palm up, waiting.