Chapter 2

Leo peered into the darkness below. "It's a staircase."

"So it is," Elias said, though his voice carried a note of surprise that suggested he had not expected steps.

Stone stairs spiraled downward, lit at intervals by small glass bulbs that glowed with a soft amber light—not fire, not sunlight, but something in between. The walls were rough-hewn, the work of hands that had shaped the earth rather than cut through it.

"Did you build this?" Leo asked, already descending.

"No. I didn't know it existed." Elias followed, his robes brushing the steps. "I've lived here thirty years and never found this entrance. The Hill-Roller took a path I didn't choose."

"Maybe it knew where it was going."

"The Hill-Roller is a collection of mismatched wheels and hope. It doesn't know anything."

Leo laughed, the sound echoing down the stairwell. "Then maybe you built it better than you think."

Elias had no reply to that.

The stairs ended in a cavern. It was not a natural cave—the ceiling was too even, the floor too smooth. Shelves had been carved into the walls, and upon those shelves sat objects that made Elias's workshop look tidy. Glass spheres containing swirling liquids. Metal frames with gears the size of dinner plates. A contraption that looked like a pair of mechanical wings, folded and waiting.

But what caught Leo's attention stood in the center of the cavern: a second Hill-Roller. This one was complete. Its wheels were perfectly round, its platform wide enough for two, its frame reinforced with brass fittings that gleamed in the amber light. A set of blueprints lay unfurled on a nearby table, covered in elegant handwriting and precise diagrams.

"You have another one," Leo said, walking around it.

"I don't." Elias approached the machine with the caution of a man meeting a stranger who wore his face. "I've never seen this before."

"Then who built it?"

Elias picked up the blueprints. His own handwriting stared back at him—the same loops, the same abbreviations, the same habit of drawing little stars next to ideas he particularly liked. But he did not remember drawing these. The date in the corner read seven years ago.

"This is impossible," he murmured.

"Or you forgot," Leo said, not unkindly. "You have a lot of stuff."

"I don't forget entire inventions."

"You forgot a door in the ground."

Elias opened his mouth, closed it, and opened it again. "That's... a fair point."

Leo climbed onto the finished Hill-Roller and tested the rope handle. It held firm. "Does it work?"

"It should. The design is superior to mine. The center of gravity is lower, the wheels are true, and the braking mechanism—" Elias stopped, squinting at a lever near the rear axle. "The braking mechanism appears to involve a parachute."

"A parachute?"

"For emergency stops. It's ambitious."

Leo grinned. "Can we try it?"

Elias looked around the cavern. A tunnel led off from the far wall, wide enough for the Hill-Roller to pass through. He could not see where it ended, but the floor sloped gently downward.

"We don't know where that goes."

"That's the point," Leo said, echoing his own words from earlier.

Elias felt the familiar warmth in his chest again. He picked up the blueprints, folded them carefully, and tucked them into his robe. "Very well. But if we encounter a chasm, we stop."

"Agreed."

"And if the parachute deploys, you owe me an explanation."

"Deal."

Leo settled onto the platform, and Elias climbed on behind him, gripping the edges of the frame. The Hill-Roller accommodated them both, though only just. Elias's knees pressed against Leo's shoulders, and his spectacles slid down his nose as they tilted forward.

"Ready?" Leo asked.

"No."

Leo pushed off.

The Hill-Roller moved smoothly, nothing like the rattling chaos of its predecessor. The wheels hummed against the stone floor, and the tunnel opened before them like a throat swallowing light. Elias held his breath as they picked up speed, the amber bulbs flashing past in a steady rhythm.

They rounded a corner and found themselves in a second cavern, larger than the first. Here, the shelves held not inventions but maps. Dozens of them, pinned to the walls, showing tunnels and chambers and underground rivers. Red lines traced paths through the earth, connecting points that Elias recognized as locations above ground: the village well, the old mill, the churchyard.

"You mapped everything," Leo said, slowing the Hill-Roller to a stop.

"I didn't. I couldn't have. I've never been down here."

"But the handwriting—"

"Is mine. Yes. I see that." Elias stepped off the platform and approached the nearest map. His fingers traced a red line that led from his own cottage to a chamber marked with a star. The note beside it read: Test site. Successful. Bring better rope.

"You did this," Leo said quietly. "You just... forgot."

Elias shook his head. "I don't forget things. I remember every failed experiment, every misplaced reagent, every hen I've accidentally turned blue. I would remember building an underground railway."

"Maybe you didn't want to remember."

That stopped Elias cold.

He looked at the maps again, at the careful lines and the precise notes. He looked at the Hill-Roller, finished and waiting, as if he had built it for someone else to find. He looked at Leo, who stood with his hands in his pockets, watching him with those bright, curious eyes.

"Why wouldn't I want to remember?" Elias asked.

"Maybe because if you remembered, you'd have to tell people," Leo said. "And if you told people, they'd come down here and take it apart. Or fill it in. Or call you dangerous and make you stop."

Elias considered this. The villagers did think him peculiar, dangerous even. They whispered about hexes and mad science. If they knew he had been carving tunnels beneath their homes, they would not ask questions. They would act.

"You're very perceptive for someone who still has baby teeth," Elias said.

"I'm ten. I have all my adult teeth."

"The point stands."

Leo laughed and climbed back onto the Hill-Roller. "So what's at the end of the red line?"

Elias looked at the star on the map, the note about better rope. "I don't know. But I suspect that's where we're supposed to go."

"Then let's go."

Elias hesitated. The tunnel ahead was dark, the amber bulbs growing sparser. He could feel the weight of the earth above him, the miles of stone and soil that separated him from the sky. But Leo was already waiting, patient and unafraid, and Elias realized that he had been waiting for someone like this his entire life.

He climbed onto the Hill-Roller, gripped the frame, and nodded.

"Forward," he said.

Leo pushed off, and they plunged into the dark. The wheels hummed, the air grew cool, and Elias felt the strange, exhilarating certainty that he was finally going home.

The tunnel opened into a chamber filled with light. Elias blinked, his eyes adjusting to the glow of hundreds of tiny glass spheres suspended from the ceiling by threads. Each sphere contained a different color, and together they painted the walls in shifting patterns of gold and blue and green.

In the center of the chamber stood a pedestal. On the pedestal rested a single object: a small brass key, shaped like an acorn.

Leo stopped the Hill-Roller and stared. "What's that?"

Elias stepped forward, his heart pounding. He reached for the key, and as his fingers closed around it, he remembered.

He remembered building this chamber. He remembered hanging the spheres, one by one, each containing a fragment of captured starlight. He remembered placing the key on the pedestal and sealing the door above, knowing that someday, someone would find it.

He had built this for a friend. He just hadn't known who yet.

"It's a key," Elias said softly. "To something I forgot I was saving."

Leo smiled. "Good. Let's go find the lock."