The Echo that came through the door wasn't one creature anymore.
It was three bodies fused together, screens and flesh melted into a single mass of limbs and static. Its faces cycled through dozens of expressions—terror, rage, joy—all wrong, all empty.
Kael fired his weapon. The sound wasn't a gunshot. It was organic, wet, like something coughing up its lungs. The projectile hit the Echo dead center and spread like black oil, eating through the screens and flesh.
The thing didn't scream. It glitched.
Its body stuttered, freezing in place for half-second intervals like a video buffering. Then it collapsed into pixels that dissolved before hitting the ground.
"Move!" Kael grabbed Elara's wrist, hauling her toward the back of the room where a maintenance shaft gaped open.
"You knew they'd find us here!"
"Counted on it." He shoved her toward the shaft. "Needed them focused on this location. Go!"
Elara dropped into the shaft, her boots hitting slick metal. The smell down here was worse—rot and ozone and something chemical that made her eyes water. She could hear Kael behind her, moving silent despite his size.
Behind him, more sounds. Wet. Skittering. The Echoes were coming.
The shaft opened into a maintenance tunnel, this one older than the metro station. Brick walls sweating moisture. Pipes overhead dripping something that definitely wasn't water. The pendant against Elara's chest had gone from frozen to burning hot in the span of a heartbeat.
"Why's it doing that?" She pressed her hand over it through her shirt.
"Getting closer to the source." Kael didn't slow down. "The deeper we go, the stronger the signal."
"Signal to what?"
"Your sister. The network. Same thing now."
The tunnel curved sharply. Elara's flashlight caught something on the walls—symbols carved deep into the brick. The same symbols from the pendant. They weren't just carved. They were growing, spreading across the surface like roots.
"Kael."
"I see them."
"What are they?"
"The language CodeX created. It's not digital or organic. It's both. Every symbol is a command, a virus, a prayer." He stopped at an intersection, head tilted. Listening. "They're ahead of us now."
"How? We've been running—"
"They don't move through space the same way we do. They're in the network. The walls. The air." His black eyes flicked to her. "You need to understand something. Down here, reality isn't fixed. CodeX corrupted the foundations. Physics breaks. Logic breaks. Stay close to me or you'll end up like them."
A sound echoed from deeper in the tunnel. Not skittering. Singing.
A child's voice. High and sweet and completely wrong in this place.
Elara, Elara, blood of my blood
Come down, come down, into the flood
The code is hungry, the network screams
Wake up, wake up, from borrowed dreams
Elara's blood went cold. "That's—"
"Your sister." Kael's jaw clenched. "What's left of her."
The singing got louder. Closer. But it wasn't coming from ahead anymore. It was coming from everywhere, the walls themselves vibrating with each word.
"She knows we're here," Elara whispered.
"She's known since you put on the pendant." Kael pulled out a second weapon, tossing it to her. It was lighter than it looked, warm and slightly damp. Like holding raw meat. "You know how to fight?"
"I know how to run really fast."
"Learn quick."
The walls started bleeding.
Not the walls. The symbols. They wept dark liquid that ran up instead of down, defying gravity to pool on the ceiling. The drops that fell sizzled when they hit the ground, eating through concrete like acid.
In the blood-shadows, shapes moved. Humanoid. Dozens of them.
"Failed subjects," Kael said quietly. "The ones who didn't make it to the cathedral. They're faster but less stable. Aim for the screens. That's where their consciousness is trapped."
"This is insane."
"Yeah."
The shapes lunged.
Elara fired on instinct. The weapon kicked in her hands, alive and angry. The projectile hit the nearest shape center mass, and it came apart like wet paper. But there were more. So many more.
Kael moved like violence in slow motion. Each shot precise. Each movement economical. He didn't waste energy, didn't flinch when claws made of USB cables raked across his arm.
Elara wasn't as graceful. She stumbled backward, firing wild, hitting more by luck than skill. One of the failed subjects got close enough for her to see its face—a woman's features stretched across a screen, mouth opening and closing in a silent scream.
She shot it between the eyes. The screen shattered, and the body collapsed into a puddle of black oil.
"Keep moving!" Kael grabbed her shoulder, pushing her forward even as he fired behind them.
They ran through tunnels that shouldn't connect, rooms that existed in impossible spaces. Elara's sense of direction was gone. Up might be down. Left might be inside out. The only constant was the pendant burning against her chest and Kael's cold hand on her shoulder, anchoring her to something real.
The singing never stopped.
They burst into a room that made Elara's brain hurt to look at.
It was a laboratory. Old equipment, mostly destroyed. But the walls were wrong. They curved inward and outward at the same time. The ceiling was too low and too high. And covering every surface were photographs.
Children. Dozens of them. All around the same age. Maybe five or six years old.
Elara's breath caught. Because she recognized one of them.
"That's me."
The photograph showed two girls. Identical. Same dark hair. Same sharp eyes. Same small scar on their chins from some forgotten accident. They were holding hands, wearing matching white dresses, standing in front of equipment that looked more like torture devices than medical instruments.
"You and your sister," Kael confirmed. "Maya. That was her name. Before."
Maya. The name echoed in Elara's head, dislodging something. Fragments of memory, buried deep. A hand smaller than hers, always cold. A voice singing her to sleep. A promise made in the dark.
We'll always be together. No matter what.
"They separated us." Elara touched the photograph, and the moment her fingers made contact, pain exploded behind her eyes.
Memory, sharp and vivid:
A white room. Bright lights. Her sister Maya strapped to a table, cables running into her arms, her neck, her spine. Screaming. The monitors showing her vitals going crazy—heartbeat, brain activity, something else. Something new.
A man in a white coat: "Subject Two is integrating successfully. Subject One, prepare for synchronization."
Elara—no, not Elara yet, just Subject One—trying to run. Strong hands holding her down. Her sister's screaming cutting off suddenly, horribly. The monitors showing Maya's consciousness spreading beyond her body, into the cables, into the computers, into everything.
A woman's voice, cold and clinical: "Subject One is rejecting the merge. Initiate memory wipe protocol. We'll try again when she's older."
Pain. White-hot. Everything dissolving.
Maya's voice, faint, desperate: "Don't make me forget. Please don't make me—"
Elara gasped, stumbling back from the photograph. Kael caught her before she fell.
"You remembered." Not a question.
"They made me forget." Her voice shook with rage. "They took her from me and made me forget she existed."
"The pendant was supposed to protect you. Keep you hidden from the network." Kael's expression was unreadable. "But it also kept the memories locked. The moment you put it on, it started breaking down the walls they built in your mind."
"Who are they? The people who did this?"
"Dead, mostly. CodeX was shut down after it went wrong. The facility burned. The researchers disappeared." He paused. "All except one."
The singing stopped.
The sudden silence was worse than the sound. In the absence of Maya's voice, Elara could hear other things. Breathing that came from the walls themselves. A heartbeat that matched the pulse of her pendant. And underneath it all, a low humming. Binary code spoken aloud.
"She's here," Kael whispered.
The far wall split open. Not a door. The wall itself peeled back like skin, revealing darkness beyond. And in that darkness, something moved.
A girl stepped into the laboratory.
She looked exactly like Elara. Same face. Same build. Same age. But her skin was translucent, showing circuitry underneath. Cables grew from her spine like wings. Her eyes were screens displaying endless streams of code.
And she was smiling.
"Sister," Maya said in a voice that was digital and human and neither. "You finally came home."
Elara's pendant burned white-hot. In her mind, she felt something snap—the last wall holding back her memories. Twenty-three years of locked-away moments came flooding back. Every day with Maya. Every promise. Every nightmare.
She remembered everything.
And she understood why she'd been running.
Because Maya hadn't just been absorbed by CodeX.
She had become it.
"I've missed you," Maya said, taking a step closer. The floor beneath her feet cracked, code spreading from each footstep like infection. "I've been so lonely. But now you're here, and we can be together again. Forever. Just like we promised."
Kael raised his weapon.
"Don't." Elara's hand shot out, stopping him. Her eyes never left her sister. "She's still in there."
"No," Kael said quietly. "She's not. Not anymore."
Maya's smile widened, showing teeth that glitched between human and something else.
"He's right, sister. I'm so much more now. And soon, you will be too." She held out her hand. The skin dissolved, revealing a skeletal framework of bone and fiber-optic cable. "Take my hand. Join the network. We'll never be apart again."
The pendant pulsed once. Hard.
And Elara heard her sister's real voice. Small. Terrified. Trapped somewhere deep in the network.
Please. Please help me. I'm so cold.
Elara's hand moved to the pendant. "If I take this off—"
"Don't," Kael grabbed her wrist. "The moment you do, you'll be absorbed. There's no saving her."
"You don't know that."
"I do." His black eyes met hers, and for the first time, she saw something in them. Grief. "Because I tried to save someone once. And I lost them to this thing. Don't make the same mistake."
Maya laughed. The sound glitched and stuttered. "Kael still thinks he's human. Still thinks he has a choice." Her screen-eyes focused on him. "But you're just like us, aren't you? Failed Subject Seven. The one who ran before they could complete the integration."
Kael's expression went flat. Dangerous.
"You're one of them," Elara breathed.
"Was." His grip on her wrist tightened. "And that's how I know there's no saving her. When you merge with CodeX, your consciousness doesn't stay whole. It fragments. Spreads. Maya isn't trapped in there. She's everywhere and nowhere. She's the network itself."
Maya's smile never wavered. "Come home, sister. Stop fighting. It's so much better here. No pain. No fear. No loneliness. Just us. Forever."
She took another step.
The cables from her spine reached forward, seeking.
Elara raised the weapon.
"I'm sorry," she whispered.
And fired.