Prologue: Day of Black Snow
Twenty years ago, the summer's solstice brought many things. It brought the black sun, and Sozin's comet. But it also brought a final end to the great hundred year war. The Avatar, Aang, and his friends invaded the Fire Nation capitol, and before the battle was won, new alliances were formed. When the war was finally over, the Avatar returned to his home, the Southern Air Temple. It has been said that he meditated every day and night, and on the fifth year, he entered the Spirit World, but never returned. To this day, no one knows why the last airbender suddenly vanished from this world. Soon, a new Avatar will be revealed from the Water Nation, and the world will be in balance for all eternity.
Kashi stared out into the cold ocean as she saw the red sails get closer and closer. She kept measuring the distance of the ships by comparing the size of the sails to her hand. First, it was the size of her fingernail; it was still too far away to be of any concern. But it was gaining quickly, and in a matter of a few minutes the sails were the size of the palm of her hand.
She was on guard duty for the day. She was to let the rest of the tribe know if a merchant ship was coming so that they could gather supplies to trade with. She'd already warned them, and her mother was preparing some soup for the men, while her uncle gathered penguin meat and seaweed roots for trading.
The ground rumbled, and she looked up to see a flaming fireball headed in her direction. She could do nothing but stand there; she had never seen anything like this before. "Kashi, look out!" Sokka called out, and tackled her to the ground just before a huge explosion shook the ground. "We're under attack!" Kashi's eyes widened. Attack?!
It didn't take long for the Fire Nation ship to bring down most of the village. Kashi tried to help fight, but Sokka grabbed her waist and dragged her away. She kicked and screamed, protesting that, "I need to help Mom!" But Sokka wouldn't let her fight. He had to get her to safety.
Katara and some of the other benders of the village were trying to both douse the flames threatening to devour the buildings and keep the Fire Nation soldiers at bay. In a few minutes, they were overpowered, and the Fire Nation was winning.
Kashi finally escaped her uncle's grasp, but when she made it back to the village, it was too late. Fire had engulfed every home, and no one could be seen. The Fire Nation soldiers and the ship were gone. "MOM!" she cried out, tears streaming down her face. She ran to where her home had once stood – a pile of ashes now – and collapsed on the ground, sobbing. "Mom, where are you?" she whispered. She touched the blue necklace on her neck as the tears freely fell into the ashen snow.
This day would forever be known as the Day of Black Snow.