At the top of a green valley, in the last house before the hills began, lived a girl named Wren. Every evening, just as the sun slipped behind the far mountains, something wonderful happened for the space of a few breaths: a path of golden light appeared on the hillside — winding up and up, stone by glowing stone, all the way to a castle on the highest peak.

By full dark it was gone. Nobody in the valley ever walked it. “That path leads nowhere,” the grown-ups said, “or somewhere you oughtn’t go.” But Wren watched for it every single dusk, and wondered.

Wren had one treasure: a small tin lantern that had been her grandmother’s. “Light it,” her grandmother used to say, “when you need to see just the next step. That is all a lantern is for.”

So on the evening this story truly begins, when the golden path unrolled across the hill, Wren lit the little lantern, took a breath to catch her courage before it could run off, and stepped out onto the first glowing stone. It was warm under her feet, like a stone that has held the sun all day. Behind her, the valley grew small. Ahead, the castle shone.

She climbed. But the path was a strange road. However far she walked, the castle never seemed to come any closer — it hung on its peak, golden and patient, always just as far away. And as the sun sank lower, the edges of the path began to dim, the far stones fading into dusk, so that she could clearly see only the few just around her.

That was when Wren understood what the lantern was for. Its little glow fell on the next stone, and the next, lighting her way one step at a time. So she stopped staring at the far-off castle, and watched her feet instead, and climbed on.

Halfway up, where the path crossed a cold and windy ledge, she found a small creature curled against a rock — a glimmer, no bigger than her two hands, the kind of little being that is made of light. But this one’s light had gone out. It shivered, grey and dim, too weak to fly.

“You’re cold,” said Wren, and knelt down. She knew that if she opened her lantern to share the flame, her own light would shrink, and the dark was coming fast. For a moment she was afraid. Then she opened the little door anyway, and let the glimmer warm itself at her flame.

The glimmer drank the light and brightened — pale, then gold, then blazing like a small sun. It leaped into the air, spun a happy circle round Wren’s head, and darted up the path ahead of her.

And where it flew, it woke the fading stones. Four, five, six of them kindled gold again, lighting a stretch of the path that had gone dark — a stretch Wren could never have crossed alone. “This way!” the glimmer seemed to say, dancing. Wren laughed for the first time all evening, and followed.

Higher up, the path forked. To the left, the way ran smooth and bright straight toward the castle, so close now she could see its golden towers. To the right, the path was dim and steep and led away from the castle altogether. Anyone could see which way to go.

But the glimmer would not fly left. It hovered over the right-hand path, glowing hard. Wren hesitated — then trusted it. She had gone only a few steps to the right when, behind her, the bright left path simply winked out into empty air over a black drop. The castle it had promised was only the last of the sunlight, caught and shining on nothing at all.

The true path grew harder as the light grew thinner. At last Wren came to a place where the way simply stopped — one glowing stone at her toes, then a gap of pure darkness, and somewhere beyond it, she hoped, the next stone.

She held up her lantern. It showed her nothing but night. To cross, she would have to step out over the dark and trust that a stone would be there — trust that it would light only when her foot came down. Her heart hammered. Then she remembered her grandmother: see just the next step. She fixed her eyes ahead, and stepped.

Her foot came down on something solid — and beneath it a stone flared gold, then the next, and the next, unrolling ahead of her into the dark as fast as she dared to walk. The path only ever lit one step ahead. You had to walk to see it. That, she understood now, was the whole secret of the golden road.

The last of the sun was a thin red line on the mountains. By its dying light, and her small lantern, and the glimmer blazing at her shoulder, Wren climbed the final stretch to the castle on the peak.

But there was no castle. There never had been. Where the golden towers had seemed to stand, Wren found only a small stone cottage with a crooked chimney, its window warm and yellow — and beside it, on a tall post, a great old lamp, the source of all the light. From below, at dusk, its glow had struck the hillside just so, and made a humble cottage look like a castle of gold.

In the doorway stood an old woman with a face like kind, cracked leather, holding a taper. “Well,” she said, smiling as if she had waited a very long time. “You came all the way up. Hardly anyone ever does.”

She was the Lamp-keeper, and every dusk for longer than she could remember she had lit the great lamp and sent the golden path down the hill — hoping that one day someone would climb it to the end. “The path can’t be finished by the strong or the swift,” she said, pouring Wren a cup of something warm. “Only by someone brave enough to take the next dark step, and kind enough to share their light along the way. You did both. Most people turn back at the first fading stone.”

She did not give Wren gold. She gave her a single spark from the great lamp, and set it inside the little tin lantern. “Now it will never go out,” she said. “Carry it well.”

Wren walked home by morning light, down an ordinary green hillside with no golden stones on it at all — but her grandmother’s lantern glowed steady and warm in her hand, and would not be put out.

That very dusk, when the golden path unrolled across the hill again, the children of the valley looked up and saw something new: a small lantern already climbing it, sure and unafraid, lighting the stones one step at a time. And this time — because someone had gone first, and left a light — they were not afraid to follow.