The small village where Tarn had lived for all her life was blocked by mountains on one side, the ocean on the other, and a raging river on the third. For anyone in this isolated delta of unfortunate terrain to trade anywhere else, a perilous journey across the mountains was needed.

The brave villagers crossed the mountains for generation upon generation before they made the decision to ford the river. Thus the town worked and worked for five long years, trying to build a bridge. Many lives were lost, as the river’s fury smashed their efforts to pieces. As happens in five years, Tarn went from being a girl to being a woman, and she felt regret for the suffering of her village. So she went to the river and lay down by its side.

“River, tell me. Why do you rage? Our village is dying and we cannot cross the uncaring mountains much longer. Will you not let us bridge your currents?”

“Young lady, I rage because I am alone. You see the uncaring mountains? They cut me off from all my brothers. And the ocean? He thinks we rivers are below him. I have no others but myself, and the emptiness of my heart fills me with rage, which I cannot contain.”

Tarn was moved by the river’s sorrow, for like his rage and rushing waters, it was powerful, deep, and dangerous. “River, if it is only loneliness that troubles you, then I will stay with you, and ease your terrible loneliness. I only ask you help my village and let them cross between your shores.”

The river swirled in contemplation before he spoke again. “Young woman, you have shown me the only kindness I have ever known. But I am a river and you are a mortal. It is not as easy as all that. I must know if you are able to fulfill your promise.”

“Whatever I must do to prove myself,” said Tarn, “you need but ask.”

“Very well,” said the river. “In the thrice ninth land of the thrice tenth kingdom stands the tallest mountain in the world. At the top of the mountain, the Lady Night watches over the world with her right eye the Moon, wearing her cloak woven with diamonds. If you can bring to me one of Night’s diamonds, I will be satisfied.”

Tarn bowed and straightaway she packed up a satchel and some warm cloaks, and set out for the tallest mountain in the world. As all the seconds ticked off in telling the tale, so many days were taken to travel the trail, and her journey brought her to the peak of the mountain at the stroke of midnight.

Tarn looked up at the lady Night and her eye the moon, wondering if the woman could hear her voice, and with all her courage she called up, begging the lady Night for a moment of her time. Three times she called, and three times the lady Night paid her no mind, but at her fourth entreaty, the Night turned her right eye to look upon Tarn, and before she could blink, the lady Night stood facing the young woman Tarn.

“I see you have traveled far to speak with me, and so you may have my ear. Come, young woman, what would you?”

Thus Tarn told the lady Night her story, and the Night listened intently until it was through, whereupon she shook her head sadly. “The river is right, but I fear you are not the measure of the task before you. The diamonds of my cloak are not meant to be held by mortal hands. Will you not be swayed?”

“Please, Lady Night. I must, for otherwise my village shall die.”

The lady Night merely shrugged her shoulders, growing as tall as the sky again, and reached up to pluck one of the diamonds from her cloak. “Take it, young woman, and rush home without delay, for I fear you will not carry it long or far.”

Tarn took the diamond from Night, and immediately felt a cold deeper than the breath of Jack the Frost and crueler than jealousy drive its needles into her body. She understood Night’s warning, and ran without delay, clenching her hand tight around the diamond.

Like the winter wind, she raced between grass and leaves and no obstacle could stand in her way. She rushed over land and mountains in thrice the time the tale was written. Soon she was running down the mountain which guarded her village, the lady Night’s diamond still held in her hands.

She reached the river and there she stopped. Her skin was pale as morning frost, her eyes clear as icicles, her hair like polished topaz. She tried to speak, to tell the river she was here with his prize, but her mouth was frozen shut. Even her eyes could not blink. She fell upon the soft, grassy banks and cried, each tear freezing on her skin.

“You have returned,” said the river. “And I see you have brought what I have asked. You have kept your promise, and I shall keep mine. Step into my waters, for I will trouble your village no more.”

Each of Tarn’s limbs was as chilled marble, but she found her feet, for the sake of her village, and stepped into the river. He no longer raged. Now his gently flowing waters lapped across her body, warming her, until bit by bit she melted away in the currents of the river.

“You will no longer need your mortal flesh,” the river told her. “I will sculpt for you a body of pearl, sand, and silver. Thus you will ever after be a part of me and I will be a part of you. By the diamond of the Lady Night, I promise, and so by both our promises we are bound.”

And that is the story of how Tarn tamed the river with a promise.