Chapter 109: THREE GROOVES

By morning, the chalk line outside the holding room had been scuffed by boots, but the inner door remained shut. A medic moved between the cots with a kettle of clean water. Eda lay beneath two blankets, her swollen knee supported on folded cloth. Bren had drawn the same bend in the Arcline branch three times, each version ending at the service drain.

Sio studied the drawings while Gumm watched a drop gather on the kettle’s spout. "Your drain brought you to the washout. But you said you passed two junctions before you saw daylight."

"One was low enough that we crawled." Bren pressed his thumbnail into a charcoal mark. "The other had a metal plate. Four cuts above a circle. Kell thought it was a warning."

"Could’ve been," Kell said from beside Eda. "There were warnings everywhere, and none of them helped."

Fern raised her wrist. Sterling’s fractured projection assembled a drainage plan from broken lines. "A four-notch service marker belongs to a pressure-relief branch. The neighboring track is missing from the thirty-eight-percent Index copy, so don’t mistake this for a complete map."

Caspian set a clean sheet over the projection and traced the surviving junctions, marking missing sections with dotted lines. "I’ll carry this. The Index and its decoder stay here with Fern." He showed Mara the paper before folding it. "It identifies the marker, not the wreck."

"That’s enough for one survey," Mara said. She touched the sealed Aureole envelope beside her elbow. "No rescue attempt without a stable approach, and you return by the parallel upper bank, not the drainage track you take out. My watch will hold the outer cutoff. Fern stays with the Index and the patients."

Angle tightened his red scarf beneath his coat while Caspian checked his pack. Rhea flexed her bandaged palm and tucked it into her sleeve. Mara looked at all four of them. "If you find the branch, mark it without leaving a trail back here. And this message stays until the courier route is cleared."

They left by the lower drainage approach under gray morning haze. Overnight water had spread pale sand across the stones. Rhea walked ahead, her ears shifting with the stream’s pitch. Square-heeled prints appeared on the northern bank, but she didn’t follow them.

"They turn away from the channel," she said. "Could be a trail someone wants noticed. We have a different one to find."

Angle inspected the prints from where he stood. "You think the scout left them deliberately?"

"I can’t tell." Rhea stepped onto a dry ledge above the current. "That’s why I’m not trusting them."

The hills gave them rust-colored mud and old drainage stone. Sio slipped on a slanted wall, and Caspian caught the back of his coat before he landed in the stream. Gumm stretched a small arm toward the water, clicking indignantly from Sio’s shoulder.

At the first fork, Caspian unfolded his paper copy. Its surviving line pointed to a narrow spillway. They followed it to a collapsed culvert packed with roots and gravel. Caspian scraped aside silt to expose masonry older than the Arcline track.

"No four-notch plate." He folded the paper against the wind. "Wrong branch. We’ll try the other."

The second channel narrowed between upright slabs worn smooth where water had passed for years. A metallic odor grew stronger. Rhea stopped beside a wall half buried in silt and brushed it with the back of her wrist. Four shallow cuts lay above a stamped circle.

Caspian matched them to Bren’s drawing. "Here. The first point we can confirm." He made a small mark on the copy without writing down the route from Safe Node Seven.

Ahead, the stream vanished beneath a hill. Angle tested the stone at the entrance with his boot. A tremor moved through the floor, and water squeezed from a crack carrying flakes of hard white paint. One caught against Sio’s boot. He recognized the finish from the Arcline carriage.

They entered single file. Rusted brackets hung from the ceiling, some still holding cables. The floor sloped toward crumpled metal lodged among collapsed stone. Beyond it, a carriage wall had folded around a support column, its white ribs buckled by the impact.

Sio approached the shell. Grease streaked the paint at shoulder height, and scrape marks led toward a gap beneath it. Someone had shifted debris there after the collision, though he couldn’t tell when. Rhea crouched near the gap, angling an ear toward the darkness.

"Water," she murmured. "And something tapping."

Angle lowered himself beside her. Three faint impacts came through the metal, a pause, then two more. Caspian examined the support column before allowing anyone closer. "Could be loose equipment. Don’t put weight on that beam."

Sio tapped the carriage panel twice with a pebble. The reply came as three measured knocks. He tapped again, more slowly, and a voice carried through the seam. "Who is that?"

"We came through the service drain," Sio said, crouching low. "Are you trapped in the prisoner branch?"

"Yes. There are others with me. The partition won’t open." A cough interrupted the speaker. "Did Bren get out?"

"He did. Kell and Eda too. They’re safe for now." A murmur rose beyond the panel, overlapping voices too distorted to distinguish.

"How many are with you?" Caspian asked, keeping his notebook steady against the rock.

"Six here. More beyond the next door, maybe. We haven’t heard them today." The speaker paused. "Tell Bren the emergency lamps are nearly gone. And don’t open the door with three grooves."

Sio remembered Bren’s sketch. "Why not?"

"The service shaft behind it is flooded. There’s a pressure gauge on our side, and the needle hasn’t dropped since the collision. Water keeps coming through the lower seal." Metal knocked near the voice. "The outer release wheel is on your side. If you turn it, the water comes into our cells."

Angle found the wheel housing beneath a folded beam, but stopped before touching it. The carriage wall supported part of the collapsed ceiling. Moving the beam without checking its load could bring the roof down. He looked at the sealed cells, his thumb catching on the red scarf tucked beneath his coat.

Sio studied the narrow gap. Someone inside pushed two fingers into the light, barely clearing the jagged edge. He searched for a visible patch of floor where he could place a portal exit. All he could see beyond the fingers were overlapping plates and shadows. An opening in the wrong place could overlap a person or buckled metal, and he couldn’t even establish whether there was room for someone to step through.

Not like this. He drew his hand back. A portal wasn’t a substitute for knowing what waited on the other side.

"We’re not touching that wheel," he told the voice. "We need to shore up the carriage and relieve the pressure before moving anyone."

"How soon?" The speaker coughed again, and someone else shifted close enough for Sio to hear fabric scrape across metal.

He looked to Caspian, who was sketching the column, beam and wheel housing. "We found you," Sio said. "We can bring people who know how to make this safe. Don’t try the door yourselves."

"Then don’t lose this place," the voice answered. The two fingers withdrew, and the weak light beyond the seam flickered.

They marked the junction and wreck on Caspian’s copy, then backed out without disturbing the bracing. At the open channel, Rhea took them up onto the parallel upper bank Mara had specified. The return required crossing dry rock above the stream rather than following their outbound footprints, and Caspian checked every bend against the landmarks he’d marked. The square-heeled scout never appeared, though Rhea kept listening behind them.

At the outer checkpoint, Mara examined the sketch while Caspian described the trapped compartment and the water pressing against the three-groove door. Her face remained still until he mentioned the voices from farther inside.

"Six confirmed alive," she said. "Possibly more. And the wrong release could drown them."

"We need braces, pumps, and someone who understands those locks," Caspian replied. "We have a location now. Not a safe way in."

Sio looked toward the holding room. Eda had been asking about those prisoners since they’d carried her inside. "We can’t leave them waiting for another guess."

Mara turned to the Aureole envelope. A watch signal sounded from the corridor; she answered through the grille and listened to the response. "The separate courier route has been checked from both ends. No sign of the ridge scout on it." She kept her hand on the envelope. "That’s not a guarantee the message gets through."

"Send it," Angle said. His scarf had collected white grit from the wreck, and he didn’t brush it away.

Mara called in a courier she recognized, checked the coded seal with them, and gave over the unmarked envelope without saying Aureole’s name. The courier tucked it beneath a waterproof layer and left by the cleared side passage. Mara waited for the outer watch’s confirming knock before turning back to them.

"It’s gone. Whether anyone answers is another matter."

From down the corridor came Eda’s voice asking if they’d found the others. Bren replied before Sio could hear the words. Sio looked at the new mark on Caspian’s map: six people behind a damaged wall, more possibly beyond it, and a flooded shaft between them and rescue.

They knew where to go now. They still had to learn how to bring anyone out alive.