In the far north of the world, past the edge of the continent, lie the fields of grinding ice that few dare traverse. And north of those, past where the icebergs calve, lives the Northern Water Tribe on sheets of ice built and maintained by their waterbenders.
But not all of the north is covered in ice and snow. In the oceans of the north there is one spot of green: the Spirit Oasis of the Northern Water Tribe where dwell the spirits from whom the waterbenders glean their power: Tui and La, Push and Pull, Ocean and Moon.
Once, rather long ago in the time when the Fire Nation sought to conquer the other peoples and rule over them, there was a chief of the Northern Water Tribe with no children, none at all. Indeed, it was expected that when he died his father's brother's son would take over leadership of the tribe and that his son would lead after him. But still the chief hoped, and still his wife beseeched the spirits, that they might have a child.
And in time a daughter was born to them, but she was weak and sickly and the healers did not think she would live to be named. In desperation, the chief and his wife took the child to the Spirit Oasis and placed her in the pool there, in hopes that the spirits of the Moon and Ocean would have mercy on them and save their daughter.
The Moon Spirit heard their plea and the girl-child began to cry, the strong cry of a healthy child. Her parents took her from the pool and when the time came they named her Yue, in honor of the Moon who had saved her and who had marked her, for when Yue had been placed in the pool of the spirits all the color had leeched from her hair and it grew like that ever after.
Now there began to be a discontent among the people of the Northern Water Tribe, for they had never been lead by a woman and the current chief had only a daughter. In times gone by a chief without a son would chose one of the young men of the tribe, of age with his daughter, to train to be chief after him, and that man would marry his daughter and so the line of chiefs would continue.
Many were in favor of continuing this custom and of allowing the chief his pick of successors, but there were some who said that the chief's father's brother's son was of the line of chiefs as well, that he also had been prepared to lead the tribe, and could do so better than any man of age to marry Yue. To end the contention, the chief decided that his daughter should marry the son of his father's brother's son. And as the years passed, that choice seemed proper.
Now it was that on Princess Yue's sixteenth birthday the Avatar returned to the Northern Water Tribe, seeking a waterbending master to teach him. And he brought with him from the Southern Water Tribe both a maiden waterbender and a young warrior as his helpers and protectors. These two were brother and sister, the only children of the chief to the south.
The Avatar and his companions soon settled into the rhythm of the Northern Water tribe, but the young warrior was restless in a land of peace after so much danger and he often sought out the company of Princess Yue. And more and more Princess Yue sought out his company for tales of the lands beyond the fields of ice and stories of his travels with the Avatar.
The two were good for each other. The young warrior brought laughter to the eyes of the somber princess and she taught him of the customs of their people, long forgotten on the other half of the world where the Southern Water Tribe had been all but destroyed by the Fire Nation.
As the weeks passed, the two grew closer and closer until there began to be whispers that the relationship between the princess and the southerner was not entirely within the bounds of propriety, rumors that Yue hoped to set her betrothed aside and wed the young warrior. When word reached Yue's ear she was distressed and resolved to break off all contact with the young warrior, but her resolve did not last long. Before a week had passed he had returned to her side, with words of hope and love and promises that he would not forget his place.
And an offer, a chance to see the world as he had seen it, from the back of the Avatar's sky bison. From above, her responsibilities and the concerns of her people seemed so much less and Yue allowed herself to relax for the first time since she had sworn off the young warrior's companionship. But the peace could not last, not when the Fire Nation sought to capture the Avatar and so remove all hope of lasting resistance to their conquest. Above the city, Yue and the young warrior were the first to see the snow begin to fall black as it mixed with the ashes released by an approaching fire nation fleet.
The Northern Water Tribe prepared for siege, thinking that the Fire Navy would not dare attack until the moon was new and the waterbenders were at their weakest. And so the Tribe was caught off guard when the Navy attacked that very day and continued their attack into the night and under the full moon.
With the benders of the Water Tribe at their strongest and those of the Fire Nation at their weakest it did not seem as though there were any way that the stronghold of the North could be taken that night, but the Fire Navy was large and they did not have women and children to defend, causing the chief to fear for his people.
And as the chief feared for his people so did Princess Yue. She took the Avatar and his two companions to the Spirit Oasis, hoping that there he would be able to entreat the spirits for aid, not knowing that one among the Fire Nation sought the Oasis for a very different reason or that another sought to take the Avatar himself captive.
Within minutes of the Avatar entering the Spirit World his companions were overpowered and his body was stolen away, across the ice fields towards the Fire Navy. By the time they had sorted themselves out enough to make pursuit a blizzard had come up and there were no tracks to be found.
Not to be daunted, the young warrior suggested that they set off upon the Avatar's bison in hopes that he would be able to see the Avatar from above. They set off, keeping low to the ground so that they would be sure to notice anyone trekking through the blizzard.
They needn't have bothered. When the Avatar returned from the Spirit World with the knowledge that Tui and La swim in the pool of the Spirit Oasis, he immediately freed himself and the light of his battle could be seen for yards, even through the swirling snow.
With the aid of his friends, the Avatar quickly drove off his foe and they returned to the Spirit Oasis with the knowledge that the Ocean and Moon Spirits swam their in the form of two koi and that, by tying themselves to the mortal world in such a fashion they had made themselves vulnerable. If the Fire Navy made it to the Spirit Oasis, they could kill the spirits and by so doing tip the balance of the world in their favor.
Unknown to them, the Admiral of the Fire Navy had lead a strike team into the Spirit Oasis with dark intent. The Admiral had wandered long and dug deep in search of anything that could give him the advantage when he was young, and knew what swam in the pool of the Spirit Oasis. He knew also that the power of the waterbenders came from the Moon Spirit and he thought that if the Moon Spirit were destroyed, the waterbenders would lose their power and the Northern Water Tribe could be easily overtaken.
The Avatar and his companions arrived only to hear the last of the Admiral's plans and to see him reach into the pool for the Moon Spirit.
But there was one among the strike team, an old General, who had wisdom enough to see what harm the loss of the Moon would be to the entire world and not just the Water Tribes. He pleaded with the Admiral to see reason and give up his foolish scheme.
The Admiral pretended to listen, but in the moment of relief that followed his apparent surrender he struck. He was quickly driven off by the angry General, but the Moon Spirit still floated limply in the pool and none could coax the spirit back to life. In the heavens above the moon vanished, and all throughout the world people cried out in horror as the night turned black as coal.
Outside the Spirit Oasis the battle raged on, but with the death of the Moon Spirit the waterbenders lost their power and were helpless against the attacking firebenders. And underneath the ice fields the ocean roiled and fumed as the Ocean Spirit mourned the death of its companion. The ships of the Fire Navy were overturned by the swell of the ocean and inside the city pale water rushed over the streets and swept the unwary from them.
In the Spirit Oasis, the Avatar and his companions prepared to fend off the General and the remnants of the strike team sure that, with the Admiral gone, he would see the wisdom in taking the Avatar captive, but the General paid no mind to any but Yue.
He asked her, in a quiet voice gone hollow from shock, if she had been truly touched by the Moon Spirit as her hair seemed to indicate. And Yue told him her tale, of how the Moon Spirit had given her life when she was a newborn.
The old general nodded and told Yue that the life the Moon Spirit had given her all those years ago could be given back, but that if Yue truly had no life of her own, as the circumstances of her birth would seem to indicate, she would not survive.
The young warrior begged Yue to stay with him and Yue's own heart faltered at the idea of leaving behind her beloved, but Yue looked to the waterbender, now bereft of her power, and she thought of how her people were even now being overrun by the Fire Navy, and Yue looked to the Avatar and asked herself how he was to master the elements and restore the balance of the world with one of the elements torn from the fabric of reality, and Yue looked to the old General and declared that she would heal the Moon Spirit, even at the cost of her life.
Yue went to the pool and took the burnt carcass of the Moon Spirit in her hands. As she held it, her life went into the spirit and as its wounds closed Yue grew weak, until the spirit was healed and Yue collapsed by the side of the pool. The young warrior reached to catch her, but even as her body fell into his arms it vanished.
Now healed, the body of the koi fell back into the pool and above it appeared the shade of Yue. The Moon Spirit had indeed died and Yue had not been able to restore it to life, so she had taken its place. Yue bid her beloved a last farewell, giving him what comfort she could, before ascending into the heavens.
The moon reappeared in the sky and the oceans stilled as the Moon and Ocean spirits resumed their eternal dance. With their waterbenders restored, the Northern Water Tribe quickly overpowered what was left of the Fire Navy and took captive all of those who had sought to conquer them. But the Admiral who had slain the Moon Spirit was not to be found, and some say that the Ocean Spirit dragged him to the depths of the sea in vengeance.
The young warrior felt keenly the loss of Yue, but he was a sworn protector of the Avatar and he buried his grief in his duties. Life went on and in time the Avatar and his companions left the Northern Water Tribe in search of an earthbending master, but that is another story.
In the far north of the world, past the edge of the continent, lives the Northern Water Tribe in a city built of ice by their waterbenders, around the only spot of warmth in that land of ice and snow: the Spirit Oasis where grass grows year round.
At the center of the Spirit Oasis there is a pool, in which swim the spirits from whom the waterbenders gain their power: Ocean and Moon, Push and Pull, Tui and Yue.