The walls got tighter the further they went.
Blancard had to turn sideways in places, his gauntlets scraping stone on both sides, and the sound carried way too far in every direction.
The air was warm and stale, thick enough that Caelum could taste the rock dust settling on his tongue.
Their lamps barely cut two metres before the dark ate everything.
Single file. No other way.
Dawson up front, then Blancard, Éloise, Kifah, and Caelum at the rear, with the spear held low because there was no space to raise it.
He kept checking behind them.
Nothing.
The scavengers hadn't followed them into the passage, which either meant they'd given up or they knew something about this route that Unit 7 didn't.
Neither option's great, Caelum thought.
Nobody spoke.
Just boots on wet stone and breathing.
Dawson called out that the slope was levelling, and nobody answered because there wasn't anything to say.
Then the passage opened.
One step, the walls had his shoulders, the next, they spat him into a corridor wide enough for four people, ceiling high enough to stand in properly.
Old cable tracks ran along the upper walls, stripped to nothing.
The floor was smoother. Worn.
Something had used this route a lot, a long time ago.
Caelum stopped and dug into his harness pouch.
The RS stone sat cold in his palm.
He pushed current into it the way he had in the mangrove, that same flow from his chest, down through his arm, into the crystal.
The stone had hummed for him back then. Glowed.
Pulled a gate open like it was the easiest thing in the world.
Here, it did nothing.
He pushed harder, enough to make his fingers tingle and his teeth itch.
The current hit the crystal and slid off.
Like pouring water onto a glass.
"Ward?" Blancard had stopped.
"Stone's dead."
Dawson turned. "Dead how?"
"I'm feeding it, and nothing's happening. It worked on the surface, in my awakening rift. Down here, it just sits there."
Dawson's eyes flicked to the ceiling. Then back to Caelum.
He didn't say anything reassuring, because Dawson didn't do reassuring, but the look on his face said he understood what it meant.
"Try again when we're higher. Move."
They moved.
The corridor forked twice.
Both times Caelum checked the ARC overlay and got garbage, broken returns bouncing off wet rock and metal deposits that could've been anything.
They took the wider path each time and kept going, Caelum marking the walls with his knife as they passed.
Kifah stopped first. First up.
Everyone froze.
"Voices," she whispered.
Caelum held his breath and listened.
Dripping water.
Blancard's raspy breathing.
Then, underneath all of it, something else.
Muffled. Distant.
Human.
Dawson drew his sword, plasma dark.
Blancard brought his good gauntlet forward.
They crept along the corridor until it cut a hard corner and dumped them into a low chamber lit by two chemical lanterns that threw ugly green-white light across the walls.
Five people on the far side. Armed.
Covered in dust and dried blood.
One had a leg splinted with strips of harness webbing, another was slumped over a datapad, barely conscious, and the other three were already on their feet with weapons half-raised by the time Unit 7 came around the corner.
Two seconds of nothing.
Everyone is pointing something at someone.
"Identify," Dawson said.
The tall girl at the front stepped forward.
Burn running up one forearm, the skin still wet and blistered.
Her uniform was ripped at the hip and dark with stains Caelum didn't want to identify.
The patch on her chest said UNIT 4.
"Unit 4. Cert trial." Voice like sandpaper. "Been down here since the main passage collapsed."
"Ceiling came down behind us too," the boy with the splinted leg added from the floor. "Cut us off from the insertion gate. Tried to loop back through the research chambers, but the scavengers were already in there."
"How long ago?" Caelum asked.
"Eight, nine hours."
The girl's eyes moved over Unit 7.
Blancard's dead arm.
Dawson's blistered forearm.
Kifah's blood-soaked bandages.
She didn't ask what happened. Didn't need to.
"You finish your objective?"
"Got what we came for," Caelum said.
She nodded once. Something tired behind it.
"Ours went sideways about four hours in. The collapse cut us off before we could recover."
Caelum held up the RS stone. "This won't take a charge. Yours?"
She made a sound that was almost a laugh. "First thing we tried. All five. Nothing."
She rapped her knuckles on the rock wall behind her.
"Stone works by syncing your resonance back to Earth, right? Finds the origin frequency and tears a rift between the two. On the surface, that's fine; the planar boundary is right there. Down here, we've got a few hundred metres of rock and metal ore sitting between us and it."
She knocked the wall again.
"Signal just scatters. Can't reach anything to lock onto."
So the stone's not broken. It's jammed, Caelum thought.
Blancard shifted his weight. "Deeper we go, the worse it gets?"
"Yeah. We tried at different spots along the corridors. Dead everywhere."
"There's a shaft," she said. "Three hundred metres east, it goes vertical. Partially collapsed and something's nested up near the top, we heard it moving. But if the stones need to get closer to the boundary..."
She trailed off because the rest was obvious.
Caelum tucked the stone back into his pouch.
The shaft wasn't just an exit.
It was the only way to get the stones working, the only way any of them were getting home.
"I'm Yara. Unit 4 lead."
Dawson looked at her cadets.
The splinted leg wasn't going anywhere fast.
The one on the datapad looked like he'd pass out if someone breathed too hard near him.
"How many can fight?"
Three fingers. Herself and two others.
"Three and five," Dawson said.
He glanced at Caelum.
Not for orders exactly, but close enough that Caelum noticed it and filed it away.
Three hundred metres of collapsed shaft.
Something alive at the top.
Eight people who could swing a weapon between two busted-up units.
What a team-building exercise, he thought bitterly.
"We take the shaft. Both units, one push. Whatever's up there, we go through it."
Yara looked at him for a beat. Measuring.
"Works for me."
Dawson didn't argue.
Blancard cracked his good knuckle against his gauntlet and pushed himself off the wall.
Kifah checked her bow.
Hands shaking. She checked it anyway.
Caelum pulled the case strap tighter against his back.
The slate's green status lights blinked through the clear panel, steady as ever, unbothered by the blood and the dark and the dead stones and the ten people who might not make it out of this hole.
Three hundred metres straight up with a busted team and a dead stone.
Could be worse. Couldn't think how, but it could be.