They had lost track of time.
Hours? Days? It didn't matter anymore. The lightless interior of the Worm didn't change, except for the faint pulse of its walls and the shudders of muscle far below their feet.
Rusty and Olmo moved like ghosts through its insides—resting when they could, feeding when they had to. Rusty tore strips from decayed armor and split open rotted packs to find rusted buckles or old tools. Olmo would take them, let the rust flake between his fingers, and share it. Every time they absorbed it, the hollow ache in their limbs eased, and the sharp pain of their wounds dulled.
They weren't invincible—just harder to break than before.
The Worm was never still.
Some days, it shook like it was thrashing in pain. Other days, it moved with a slow, rolling gait, as though drifting through unseen waters. Both were dangerous.
They had also learned to fight together. When a knot of pale, many-legged things had scuttled out of the walls earlier—a kind they hadn't seen before, with faces like eyeless lampreys—Rusty had waded in with her fists, her blows cracking through the soft armor only after they passed through clouds of rust Olmo kicked up. He had taken to carrying a pouch of rusted fragments, flinging them like stones to weaken enemies before she struck.
Later, a swarm of beetles with ridged, almost metallic shells had dropped from the ceiling. Olmo's rust-sense gave them seconds of warning, enough for Rusty to yank him aside before the first ones landed. Even with that advantage, they finished the fight panting and bleeding, leaning against the pulsing wall to catch their breath.
Now, they sat slumped in another tunnel. The air here was heavy and wet, smelling of iron and bile.
Rusty ran her bandaged fingers over the Worm's wall. Her hand brushed a deep gouge in the flesh. Not an old scar. The edges were still wet, faint threads of white tissue trembling like exposed nerve.
"These are fresh," she muttered.
Olmo glanced over from where he sat picking dried rust from a rib of bone. "Maybe those creatures chew at it. Feed on the flesh when people like us… aren't around anymore."
"Maybe," Rusty said, still tracing the wound. "But these feel… different. Like something else made them."
Olmo tilted his head. "What else could there be in here?"
Rusty didn't answer. The idea sat wrong in her stomach.
Before she could think on it more, the Worm lurched violently beneath them. They staggered, bracing against the walls. Another violent shudder followed—then a deep, wet roar from somewhere behind them.
The flesh of the tunnel rippled, bulging. Rusty's instincts screamed.
"Move!" she barked.
They started forward, the tunnel quaking around them. Then she saw it—rolling toward them from the dark behind: a flood of greenish-yellow liquid, frothing and hissing as it ate into the walls. The smell hit her—acid, sharp enough to sting her eyes.
"Gastric juice," she spat. "Run!"
She didn't waste time arguing with herself. She grabbed Olmo around the middle and took off, boots slapping against the slick floor. The acid was gaining, eating through everything it touched.
She knew she couldn't outrun it.
"Olmo! Think! Can you use the rusted bodies around us—make platforms?"
He twisted in her grip to look, panic flashing in his eyes. "I can't! That's—going from beginner to… whatever that is! Too sudden!"
"It's our only shot!" she shouted.
Rusty dove toward a cluster of half-dissolved corpses and kicked them toward him. "Just keep them together—I'll do the rest!"
Olmo clenched his teeth, focusing. The rusted armor and bones twitched in the air, jerking into a loose, shifting pile. The effort made his forehead bead with sweat.
She adjusted her grip so he was facing away from the flood, keeping his body between her arms like a shield. Her boots hit the first platform and pushed off. The makeshift bridge wobbled under them, Olmo's concentration flickering, but he held on.
The roar behind them grew louder. A spray of acid splashed against her back, searing through the fabric—skin stinging hot. She gritted her teeth, ignored the pain, and leapt again.
The rust bridge began to fall apart as they reached the next stretch of tunnel, but it had been enough. The acid slammed into the spot they had been seconds before, hissing angrily, devouring the floor.
Rusty stumbled to a stop, still holding Olmo. Her breath was ragged, her back burning.
Olmo sagged in her grip, pale but alive. "Told you… not mastery level…"
"You did fine," she said between breaths, setting him down gently. "We're still breathing. That's mastery enough."
They didn't move for a while—both staring back at the steaming ruin behind them.
Olmo leaned against the wall, chest still heaving. "Was that—" he swallowed, "—the Worm trying to vomit?"
"Probably," Rusty said. Her voice was tight. She was still listening — not just to Olmo, but to the Worm itself. The movements hadn't slowed. If anything, the rippling muscle under their feet was jerking harder, almost panicked.
It wasn't random. It felt like something was happening outside. Something hurting it.
Rusty's gaze swept the tunnel. There were wounds here too, fresher than the others — claw marks, deep and deliberate, like something had raked through the flesh. She could see blood seeping from them, dark and viscous, pooling in the grooves of the floor.
Olmo stepped closer, frowning. "Wait. That—" He pointed. "That wall was clean just now."
They both watched as a stretch of unmarked flesh in the distance suddenly flickered, replaced by a torn, bleeding gash. Like the wound had been… pushed inside.
Rusty's stomach turned. "It's fighting something out there," she muttered. "And dragging the damage inward."
"That's a thing it can do?"
"I guess so. Not sure if we want to stick around and watch it happen again."
Another violent shudder swept through the tunnel — the same rhythm as before the acid flood. That was all the warning Rusty needed.
"Move. Now."
They started running again. The floor pitched under them, slick with blood and bile, but their footing was sure. Olmo kept glancing behind them, like he was waiting for the flood to come back. Rusty kept her eyes forward. She'd learned to trust the Worm's movements — the hard way.
They passed more wounds as they went, some shallow, some deep enough to glimpse strands of pale muscle beneath. Each one was fresh. Each one reeked of iron and rot.
Somewhere between those gashes, the air began to change. A tang crept in — familiar, metallic, but sharper than blood. Olmo slowed, nose twitching.
"Rust," he said quietly. "It's coming from the walls."
She stopped and pressed her hand to one of the deeper wounds. Her palm came away stained orange-brown. The flesh here was grainy, breaking apart under her fingers. It wasn't just bleeding — it was rusting from the inside out.
Olmo's eyes lit faintly in the gloom. "I can feel it. Everywhere."
The Worm shuddered harder now, the walls rippling like waves. Rusty didn't know how much further they had left to go, but she was done being a passenger in whatever nightmare ride this thing was having.
She stepped back from the wound, squaring her stance. "If this is rusted through… maybe we can make our own way out."
"You want to punch through the Worm's insides?"
"You have a better idea?"
He didn't answer — just started digging into his pouch and flinging what was left of their rusted scraps at the wound. The wall hissed where they struck, the rust eating deeper into the tissue. Rusty began hammering her fists into the softened spot, each impact sinking further, the smell of rot and iron growing thick.
The Worm let out a muffled, awful sound — somewhere between a roar and a groan — vibrating through their bones.
Then, from somewhere far ahead, a tearing noise ripped through the air, followed by a rush of cold wind. For a moment, Rusty thought she'd done it — opened a hole. But the draft wasn't coming from the wall in front of them.
"Did you feel that?" Olmo asked.
Before she could answer, the ceiling above them convulsed. The ground shook. And from somewhere distant, a deep grinding began — stone against stone.
"What's it doing?" Olmo asked, bracing himself.
Rusty's eyes widened. "It's… swallowing. Rocks. Probably trying to plug whatever's hurting it from the outside."
The grinding grew louder — then the first stone chunks rained down, bouncing and clattering across the slick floor. One hit near Olmo's feet, exploding into shards. Another smashed against the wall beside Rusty, splattering her with orange grit.
"Close enough to the mouth," she said, backing away from the falling debris. "We're not punching our way through here."
Olmo glanced back down the tunnel, where more rocks were already tumbling in. "So we just… head for the mouth?"
"Unless you want to get buried alive, yeah."
Neither of them looked back as they started moving again — faster this time, the draft growing stronger, and the roar of the Worm's unseen battle still echoing in the dark behind them.