Chapter 1

He gave it a final polish with his sleeve, smearing a fresh streak of something green across the brass. The contraption—he called it the Hill-Roller Mark IV, though Marks I through III had disassembled themselves in spectacular fashion—sat in the center of his workshop like a metallic beetle on its back. Two large wooden wheels, banded with iron, flanked a low platform just big enough for one person to crouch upon. A rope handle jutted from the front, frayed at the end.

“Perfection,” Elias murmured, and the dust motes in the sunlight seemed to agree.

He lived alone at the edge of the village, in a stone cottage whose roof sagged under the weight of fifty years of salvaged curiosities. The villagers called him peculiar, which he was. They called him dangerous, which he was not, though his last attempt at a self-stirring cauldron had turned a neighbor’s prize hen blue for three weeks. The hen was fine now. The neighbor still crossed the street when he saw Elias coming.

Elias wanted company. Not the kind that came with side-eyes and whispered prayers for protection from hexes, but real company. Someone who would say “What does this lever do?” instead of “Don’t touch anything, he’s a madman.”

He was contemplating whether the Hill-Roller needed a bell when a knock came at the door.

Not a timid knock. A firm, curious knock, the kind delivered by someone who had already decided they wanted to see what was inside.

Elias opened the door to find a boy standing on his stoop. The boy had bright eyes and a mop of brown hair that looked like it had lost a fight with a thistle bush. He held a slingshot in one hand and a look of pure, unfiltered interest in the other.

“Are you the alchemist?” the boy asked.

“I am.” Elias adjusted his spectacles, which were smudged with something that might have been mercury. “And you are?”

“Leo.” The boy leaned sideways to peer past Elias into the workshop. “I heard you make things that explode.”

“I make things that perform controlled, scientific reactions. Occasionally those reactions produce a satisfying report.”

“So yes, then.”

Elias found himself smiling. “What brings you here, Leo? Most children your age are warned to stay away from my cottage.”

“That’s why I came.” Leo shrugged, as if the logic were obvious. “If everyone’s afraid of something, there’s usually a reason worth finding out.”

Elias considered this. He stepped aside and let the boy enter.

Leo walked through the workshop with the careful reverence of a museum visitor, except museums did not usually have bubbling vials or a suspended cage of clicking brass gears. He stopped before the Hill-Roller Mark IV and tilted his head.

“What’s this?”

“My latest invention. It’s designed to roll down the big hill behind my cottage at considerable speed. I call it the Hill-Roller.”

“Does it work?”

“Work is a strong word. It functions. Whether it functions well has yet to be determined.”

Leo ran a hand along one of the iron bands. “Can I try it?”

Elias blinked. “You want to ride it?”

“Yes.”

“Down the hill?”

“That’s the point, isn’t it?”

The alchemist had expected hesitation, bargaining, perhaps a demand for proof of safety. He had not expected a ten-year-old to treat his rickety contraption as an obvious invitation. He felt something warm and unfamiliar settle in his chest.

“There are treasures at the bottom,” Elias said, because every great adventure needed a promise of reward. “Alchemical curiosities I’ve hidden along the way. If you make it to the end, they’re yours.”

Leo grinned. “What happens if I don’t make it?”

“Then you’ll have a very exciting story and possibly a bruise.”

The boy climbed onto the platform without another word. He gripped the rope handle, crouched low, and looked back at Elias with bright, expectant eyes.

“Push me?”

Elias pushed.

The Hill-Roller lurched forward, wobbled dangerously, and then caught the slope with a shudder that rattled every bolt. Leo whooped as the wind whipped his hair back. The wheels bounced over stones, skidded around a patch of loose gravel, and picked up speed until the cottage behind them shrank to a dot.

Elias ran after it, his robes flapping, his spectacles fogging. He had not planned for this part. He had assumed the boy would ride, reach the bottom, and return on foot. He had not accounted for the possibility that the Hill-Roller would veer left at the fork and disappear into the Old Woods.

“Leo!” he called, but the wind stole his voice.

He rounded the bend to find the contraption stopped—not crashed, but stopped—at the edge of a clearing. Leo stood beside it, pointing at something in the grass.

“There’s a door,” Leo said.

Elias caught up, gasping. “A door?”

“In the ground. With a handle shaped like a snake.”

The alchemist looked down. A brass ring, coiled in the likeness of a sleeping serpent, lay half-hidden among the weeds. He had never seen it before. He had lived here for thirty years and never once found this clearing.

“I don’t suppose you know what’s under it?” Leo asked.

Elias’s heart beat faster. “I have a theory.”

“Good.” Leo grabbed the ring and pulled. “Let’s test it.”