Chapter 33

The red emergency lighting turned the corridors into arteries. Cass's shadow stretched and contracted with each pulse of the alarm, a dark twin racing ahead of her toward the central filtration hub.

She knew these passages. Had mapped them during her first week on the station, back when she'd thought knowing the layout would keep her safe. The hub was three levels down, accessible through the maintenance shaft near the hydroponics bay or the main access corridor that wound through the residential quarter.

The maintenance shaft would be faster.

She veered left at the next junction, nearly colliding with a technician stumbling in the opposite direction. The woman's face was pale, her uniform streaked with something dark.

"Don't—" the woman started, but Cass was already past her.

The shaft entrance stood open. Someone had overridden the lock. Cass grabbed the ladder rungs and dropped, her boots hitting every third rung, the metal singing under the impact. Her palms burned. She didn't slow down.

Marcus's voice echoed in her memory: The filtration system is the station's lungs. If it stops breathing, we've got maybe forty-eight hours before the air turns toxic.

Code Black meant casualties. Multiple casualties.

The transmission had cut off before finishing whatever it was going to say about Marcus.

She hit the bottom level and ran. The corridor here was narrower, lined with pipes and conduits that hummed with the station's mechanical heartbeat. Except some of them weren't humming anymore. Some of them were silent.

The smell hit her before she reached the hub entrance. Copper and ozone and something else, something chemical that made her eyes water.

The door was open. The emergency lighting inside had failed completely, leaving only the glow from the control panels and the beam of a single dropped flashlight rolling slowly across the floor.

"Marcus?" Her voice came out smaller than she'd intended.

No answer. Just the alarm, muted here but still insistent, and a hissing sound that might have been a ruptured pipe or might have been something worse.

She picked up the flashlight. Swept it across the room.

The filtration hub was a cathedral of machinery, three stories of tanks and filters and pumps that processed every molecule of air the station's inhabitants breathed. Catwalks crisscrossed the space at different levels. The main control station sat on a platform in the center, surrounded by readouts and monitors that usually displayed a steady stream of green indicators.

Now half of them were red. The other half were dark.

The flashlight beam found the first body near the base of the primary filtration tank. A man in engineering coveralls, his face turned away, one arm extended as if reaching for something. Cass forced herself to move closer. Not Marcus. Someone younger, with a tattoo of circuit patterns running up his forearm.

She'd seen him before. In the mess hall. He'd always sat alone, working through equations on a tablet while he ate.

The flashlight beam trembled. She steadied her hand.

"Cass."

She spun. The beam caught Soren at the entrance, his weapon drawn, his expression unreadable in the red-tinged darkness.

"I told you to wait," he said.

"Where's Marcus?"

Soren moved into the room, his boots careful on the wet floor. The liquid wasn't water. It was too viscous, too dark. "We don't know yet. The team that responded found—" He gestured at the body. "Three dead so far. No sign of Marcus or the two other engineers who were on shift."

"The transmission said his name."

"The transmission cut off." Soren's radio crackled. He raised it. "Go ahead."

"Sir, we've got movement on the upper catwalk. Northeast quadrant. Can't get a visual."

Soren's jaw tightened. He looked at Cass. "Stay behind me."

She didn't argue. They moved together toward the metal stairs that spiraled up to the catwalk system. The hissing sound grew louder. Definitely not a pipe. It had a rhythm to it, almost like breathing.

The catwalk swayed slightly under their weight. Cass kept one hand on the railing, the other holding the flashlight. Below them, the filtration tanks loomed like sleeping giants, their surfaces reflecting the emergency lighting in fractured patterns.

"Marcus?" Soren called out. "This is Security Chief Soren. If you can hear me, identify yourself."

The hissing stopped.

In the silence that followed, Cass heard something else. Footsteps. Light and quick, moving away from them along the catwalk.

"There." She pointed. The flashlight beam caught a figure disappearing around a corner, too far away to identify but moving with purpose, not panic.

They followed. The catwalk branched, connecting to different levels of the filtration system. Soren took the lead now, his weapon raised, his movements professional and controlled. Cass stayed close, her mind racing through possibilities.

Marcus had a dead man's switch. He'd made himself necessary. If something happened to him, if he didn't check in at regular intervals, certain information would be released. He'd told her that himself, sitting in his workshop, surrounded by his equations and his paranoia.

But what if the dead man's switch wasn't about protecting himself? What if it was about protecting something else?

They rounded the corner. The catwalk opened onto a maintenance platform that overlooked the primary oxygen recycler, a massive cylindrical structure that dominated the center of the hub. The figure stood at the far end of the platform, silhouetted against the glow of a control panel.

Not Marcus.

Too small. Too slight.

"Hands where I can see them," Soren said.

The figure turned. The emergency lighting caught her face, and Cass's breath stopped.

Lena. The girl from the Rattle Ward. The one who'd drawn the pictures. The one who'd known about the patterns before anyone else.

She looked different. Her eyes were clearer, more focused. Her hands were steady. And she was holding something—a small device with a blinking red light.

"You shouldn't be here," Lena said. Her voice was calm, almost gentle. "None of you should be here."

Soren's weapon didn't waver. "Put down whatever you're holding."

"It's not a weapon." Lena looked at the device, then at Cass. "It's a key. Marcus gave it to me. He said if anything happened, if they tried to stop him, I should use it."

"Use it for what?" Cass asked.

"To open the doors." Lena smiled. It was the saddest smile Cass had ever seen. "All of them. The ones they locked. The ones they pretended didn't exist. The ones where they kept the others."

"What others?" Soren's voice was sharp.

"The ones like me." Lena's thumb moved over the device. "The ones they infected. The ones they studied. The ones they called Patient Zero through Patient Forty-Seven." She looked at Cass again. "Your brother knew. Marcus knew. They were trying to help us. But the Council found out. They sent people to stop him."

The bodies downstairs. The casualties. Not an accident. Not a malfunction.

"Where is Marcus now?" Cass asked.

"Safe. Hidden. He knew they'd come for him eventually." Lena's expression shifted, something harder moving behind her eyes. "He knew what they did. What they're still doing. He couldn't stop them alone. So he built a switch. And he gave me the key."

Soren took a step forward. "Lena, listen to me. Whatever Marcus told you, whatever you think you're doing—"

"I'm not thinking." Lena's thumb pressed down. The device beeped once, sharp and final. "I'm remembering. We're all remembering now."

The lights in the hub flickered. Then they changed. The red emergency lighting shifted to white, bright and clinical, the kind of light that belonged in medical facilities and laboratories.

And somewhere in the station, deep in the sections that weren't on any official map, Cass heard doors opening. Not one. Not two. Dozens of them, the sound echoing through the ventilation system like a mechanical exhalation.

Lena dropped the device. It clattered on the metal platform, its light still blinking.

"They're awake now," she said. "All of them. And they're coming home."