Chapter 1

The air in the Sunken Metro tasted of wet iron and sweet, decaying orchids.

Kael adjusted his grip on the pry-bar, his knuckles white against the dark metal. "Stay behind the yellow line, Nia," he whispered, his voice echoing too loudly in the cavernous tunnel.

Above them, the arched ceiling of the subway station was pierced by massive, glowing crystal roots. They pulsed with a soft violet light, illuminating the platform where the "Silver Worm"—a rusted, ancient train car—sat frozen in time. Thick, bioluminescent vines wrapped around the carriage like the tentacles of a loving kraken, holding the metal together even as it disintegrated.

"I hear it humming," Nia said. She wasn't behind the yellow line. She was right beside him, her small boots splashing in a puddle of iridescent water. She was eight years old and entirely unafraid of the dark.

"That’s just the ventilation shafts," Kael muttered, jamming the pry-bar into the seam of the train doors. "Or a Draugr rat. Keep your eyes open."

"No, it’s a song," Nia insisted. She tilted her head, her messy braids swaying, and began to hum a melody. It was a simple, lilting tune, three notes rising and falling.

Kael paused. The tune tugged at something deep in his chest—a memory of warmth, of a fireplace, of a time before the forests ate the cities. But he pushed it down. Nostalgia didn't fill bellies.

He put his weight into the bar. With a screech that sounded like a dying banshee, the pneumatic doors forced open.

The smell of trapped time rushed out—dust, stagnant air, and old fabric.

"Clear," Kael signaled, stepping inside.

The interior was a tomb of the Old World. Plastic skeletons sat in rows, still clutching faded briefcases and advertisements for Mars Colonies that never happened. The crystal roots from the ceiling had punched through the roof of the car, casting dappled shadows over the seats.

Kael moved efficiently, checking the overhead bins for preserved rations or batteries. "Nothing," he sighed. "Just dust."

"Look," Nia whispered.

She was standing near the back of the car, pointing at a skeleton in a business suit. In its lap sat a pristine, metallic box, untouched by the rust that had consumed everything else. It was silver and sleek, no bigger than a loaf of bread.

"Nia, don't," Kael warned, sensing the shift in the air.

"It’s calling me," she said, taking a step forward.

"Nia!"

She ignored him. She reached out, her small fingers brushing the silver box.

The train car groaned.

The metal floor, weakened by centuries of moisture and the weight of the crystal roots, gave a sharp *crack*. The entire rear section of the car dipped violently. The rusted undercarriage shrieked as it tore away from the frame.

Nia yelped as the floor beneath her tilted forty-five degrees. Below the gap, dark, oily water churned, waiting to swallow them.

She slid. Her boots scrambled for purchase on the slick metal, but there was nothing to grab. She tumbled toward the jagged hole where the floor had vanished.

"Kael!"

Kael didn't think. He didn't calculate the structural integrity or check for exits. He lunged.

He threw himself across the tilting aisle, sliding past the plastic skeletons. He reached out, his hand closing around Nia’s wrist just as she slipped over the edge.

The jolt nearly dislocated his shoulder. Kael slammed his chest against a support pole, his legs dangling over the abyss, holding Nia’s entire weight with one hand. The train groaned again, tilting further. They were going to fall. The metal was shearing.

Kael looked down at Nia’s terrified face, her eyes wide and wet, reflecting the violet crystal light.

* Not today,* he thought. *Not her.*

He squeezed his eyes shut and pulled not with his muscles, but with his blood. He felt the familiar, heavy thrum in his veins—the gravity magic he usually suppressed to avoid attracting predators.

He screamed, a raw sound of effort. A ripple of distortion, like heat haze, flared around his arm.

Gravity inverted.

For a split second, "down" became "up." Kael swung them both backward, defying physics, hauling them up the slope of the floor as if they were weightless. They flew through the air, crashing hard onto the solid, moss-covered concrete of the station platform just as the rear of the train car broke off completely and plunged into the water below.

* Splash.*

Silence returned to the metro, save for their heavy breathing.

Kael lay on his back, staring at the crystal roots, his arm throbbing. "I told you," he gasped, his voice shaking. "I told you to stay back."

He rolled over to scold her, to tell her they were leaving, that they were never coming back to this death trap.

But Nia wasn't looking at the water. She was sitting cross-legged on the moss, clutching the silver box to her chest. She had refused to let go of it, even when she fell.

"It still works," she whispered.

She pressed a button on the side.

A beam of soft blue light shot up from the box, fanning out into a hologram. Suddenly, the damp, dark ceiling of the subway vanished, replaced by a projection of a clear, starry night sky—the sky as it looked before the smog and the spores.

And then, the music started.

It wasn't a siren or an alarm. It was a piano. A gentle, rolling lullaby. The exact three notes Nia had been humming.

Kael’s anger evaporated. The adrenaline drained out of him, leaving him hollow and aching. He crawled over to her, sitting beside her in the blue glow of the hologram.

He remembered the song now. Their mother used to hum it while cooking, back before the sickness took the village. He had thought he’d forgotten the sound of her voice, but the music brought it back, clear and warm.

"See?" Nia said, leaning her head on his shoulder. "It wasn't dangerous. It was just lonely."

Kael put his arm around her, pulling her close. The ruins were dark, and the world above was harsh, but here, in the light of a bottled star, they were home.

"Yeah," Kael whispered, closing his eyes and listening to the melody. "It’s a good song, Nia."