The horse was steadily dragging a score of blocks of granite, so heavy that the sled made deep ruts in the black earth.

When the man saw the gods he waved and called good morning cheerfully. He pointed to the rising sun, and he winked at the gods. Then he unhitched his horse from the rocks and let it graze while he began to manhandle the first of the granite blocks into the trench he had already dug to receive it.

“The horse is indeed strong,” said Balder, most beautiful of all the Aesir. “No normal horse should be able to drag rocks that heavy.”

“It is stronger than we imagined,” said Kvasir the wise.

“Ah,” said Loki. “The horse will soon tire. This was its first day on the job. It will not be able to haul that many stones every night. And winter is coming. The snows will be deep and thick, the blizzards will be blinding, and the way to the mountain will be difficult. There is nothing to worry about. This is all going according to plan.”

“I hate you so much,” said Freya, who stood unsmiling beside Loki. She walked back to Asgard in the dawn and did not stay to watch the stranger build the foundations of his wall.

Each night the builder and the horse and the empty stone-boat left for the mountain. Each morning they returned, with the horse dragging another twenty blocks of granite, every block larger than the tallest man.

Each day the wall grew, and by evening it was bigger and more imposing than it had been before.

Odin called the gods to him.

“The wall is growing apace,” he said. “And we swore an unbreakable oath, a ring-oath and a weapon-oath, that if he finishes building his wall in time, we will give him the sun and the moon and the hand in marriage of Freya the beautiful.”

Kvasir the wise said, “No man can do what this master builder is doing. I suspect that he must be something other than a man.”

“A giant,” said Odin. “Perhaps.”

“If only Thor were here,” sighed Balder.

“Thor is hammering trolls, away in the east,” said Odin. “And even if he were to return, our oaths are mighty and binding.”

Loki tried to reassure them. “We are like old women, getting ourselves all worried about nothing. The builder cannot finish the wall before the first day of summer, even if he is the most powerful giant in the land. It is impossible.”

“I wish Thor were here,” said Heimdall. “He would know what to do.”

The snows fell, but the deep snow did not stop the wall-builder, and it did not slow Svadilfari, his horse. The gray stallion pulled his sled, piled high with rocks, through snowdrifts and through blizzards, up steep hills and down again, through icy gorges.

The days began to get longer.

Dawn came earlier each morning. The snows began to melt, and the wet mud that was exposed was thick and heavy, the kind of mud that clings to your boots and drags you down.

“The horse will never be able to haul those rocks through the mud,” said Loki. “They will sink, and he will lose his footing.”

But Svadilfari was sure-footed and implacable, even in the thickest, wettest mud, and he hauled the rocks to Asgard, although the stone-boat was so heavy it cut deep gashes into the sides of the hills. Now the builder was hauling the rocks up hundreds of feet and manhandling each rock into place.

The mud dried and the spring flowers came out: yellow coltsfoot, and white wood anemones in profusion—and the wall being built around Asgard was a glorious, imposing thing. When it was finished it would be impregnable: no giant, no troll, no dwarf, no mortal would be able to breach that wall. And the stranger continued to build it with relentless good humor. He did not seem to care if it rained or it snowed, and neither did his horse. Each morning they would bring the rocks from the mountains; each day the builder would lay the granite blocks upon the previous layer.

Now it was the last day of winter, and the wall was all but completed.

The gods sat on their thrones in Asgard, and they spoke.

“The sun,” said Balder. “We have given away the sun.”

“We placed the moon in the sky in order to mark off the days and the weeks of the year,” said Bragi, god of poetry, moodily. “Now there will be no moon.”

“And Freya, what would we do without Freya?” asked Tyr.

“If this builder is actually a giant,” said Freya, with ice in her voice, “then I will marry him and follow him back to Jotunheim, and it will be interesting to see whom I hate more, him for taking me away or all of you for giving me to him.”

“Now, don’t be like that,” began Loki, but Freya interrupted him and said, “If this giant does take me, and the sun and the moon, then I ask only one thing from the gods of Asgard.”

“Name it,” said Odin all-father, who had said nothing until now.

“I would like to see whoever caused this calamity killed before I go,” said Freya. “I think it only fair. If I am to go into the land of the frost giants, if the moon and the sun are to be plucked from the sky and the world plunged into eternal darkness, then the life of the one who got us to this point should be forfeit.”

“Ah,” said Loki. “The apportioning of blame is so difficult. Who remembers exactly who suggested what? As I recall, all the gods share equally in this unfortunate mistake. We all suggested it, we all agreed to it—”

“You suggested it,” said Freya. “You talked these idiots into it. And I will see you dead before I leave Asgard.”

“We all—” began Loki, but he saw the expressions on the faces of all the gods in that hall, and he fell silent.