He followed her gaze and saw a bit of copper looped through the collar screw. Newer than the rust around it.

“Alarm?” he said.

“Maybe count line. Maybe route mark. Maybe bait.” She cut it free, sniffed it, then dropped it into the water channel. “No more talking unless we need it.”

They moved again, slower now. The root mats thickened, hanging in curtains from support racks above. Elias had to turn sideways through some of them, and each twist sent a dull blade through his ribs. He hated how much noise pain made of his breathing. He hated more that Mara could hear it.

Then a small hand caught his sleeve from the dark and he jerked so hard his side lit with pain.

Lina pressed a finger to her lips from inside a service hollow in the wall. Her breath hitched like she had been swallowing panic for minutes. Wet prints marked the metal lip below her boots, and bits of torn root clung to her sleeves. "I followed your steps," she whispered before he could speak. "And her knife on the roots. I heard you talking. The sounds behind me changed."

For one stupid second, relief hit first. She was alive, here, close. Then anger followed it, sharp and useless.

“What are you doing?” he hissed.

She climbed out carefully, bruised arm held tight against herself. Damp roots had caught in her hair. “Following,” she whispered. “You were gone too long.”

Mara stared at her as if she had appeared out of the wall itself. “No.”