Takes place during Episode 1, "Welcome to Republic City". (This was posted as Chapter 8, but moved to keep the oneshots in chronological order.)
Korra had never really had to say good-bye before.
When Tenzin and his family left the South Pole, she refused see them off. She felt too disappointed and bitter to be able to wish them well.
Katara was the first person with whom she ever bade an emotional farewell. She wasn't just Korra's teacher; she was her friend. And, Korra realized, she was probably the one who would most understand her reasons for leaving.
Katara was one of the few people she would miss. But she wasn't the only one. Korra realized that there were two others to whom she needed to say good-bye.
Once outside the compound, Korra rode Naga through the tundra, heading north until they reached the igloo. Her parents came out of the house, having heard Naga's growl. "Korra!"
She slid down from the saddle and ran up to hug them, the way she always had when she was younger. She remembered being so attached to her parents, a feeling that had faded as she grew older and focused on her training.
Her parents typically visited her every few weeks. Korra would show them the progress she was making – they were the only people she could actually show off to.
It was rarer for Korra to visit their small home. But she enjoyed those visits for all they were worth. Senna would make her special tea, and they would eat a meal together like a normal family. The house was small and cozy, designed for simply living, while the big compound had been built for bending.
Senna pulled away and held Korra at arm's length. "This is a nice surprise. I'm so glad you're here!"
Korra smiled, but her eyes were sad. "I'm sorry. I don't have much time."
Her parents' expressions changed when she said that. It reminded her of how Katara had looked sadly at Tenzin. "You're not staying, are you?"
Tonraq glanced at Naga, who was still standing, as though waiting to get going again. "The White Lotus aren't with you, are they?" He already knew the answer.
"No. Only Katara knows I'm gone." Korra shrugged. "I just couldn't leave without saying good-bye."
"Leave? And go where?" Senna asked, not understanding.
"Republic City, in the United Republic of Nations. Master Tenzin lives there. He couldn't stay here to teach me airbending. So I'm going to learn there."
"The city …" Tonraq trailed off, and Korra could guess what he was thinking. Korra had never left the South Pole. She only heard about the rest of the world from the people she knew who had seen (or even helped build) such places. "Will you be all right, on your own?"
"I won't be alone. I'll have Naga with me for the journey, and Tenzin and his family in the city."
Senna and Tonraq exchanged sad, concerned glances. They thought they had gotten used to the idea that they had to let their daughter go, so she could become the Avatar she was meant to be. They had even allowed her to live away from home for that reason. But having her live on another continent, indefinitely, wouldn't be easy for any of them.
Korra watched them cautiously. "Are you mad?"
"No," Senna said quickly. "Just surprised. I wish you'd told us sooner."
"I just decided an hour ago," Korra said frankly. Then she added, "It's not forever. I'll come back – and when I do, I'll be an airbender." She didn't say airbending master because she didn't know how long that element would take, and she didn't know how long it would be before she came back.
Senna nodded in acceptance. They had learned, long ago, that they couldn't stop Korra from gong after what she wanted. Korra put on a brave smile, trying to show her gratitude.
Tonraq spoke up, sounding apologetic as he said something he'd thought for a long time. "Korra … I'm sorry if we haven't always been there for you."
Korra blinked at him, looking concerned. "That's not true." Her parents had always been a presence (if not a constant) in her life. Senna had been there to help her through puberty, and showed her how to make armbands (the only real accessories Korra wore, mainly because they reminded her of her mother). When she turned fourteen, Tonraq had taken her ice-dodging (he had had a long argument with the White Lotus members about it, until Katara intervened and said she should be able to have that rite of passage). They were the ones who had advocated for her to keep Naga when she found the polar-bear dog lost in the tundra. Tonraq had taught her how to train the animal, glad that she could have a companion even when her parents weren't there. They had done the important things that all parents were expected to do for their child.
Still, Korra felt some regret, knowing that she had spent more time with the White Lotus than with her parents. She had usually been too busy to miss them as they gradually distanced themselves from her; but now she wasn't going to see them again, probably for a very long time.
She wondered vaguely if they would have any more children, to fill any hole created by her own absence. She wouldn't be there to see them. And they wouldn't be with her to watch her finish adolescence and mature into adulthood.
"Come here," Senna said, opening her arms again. Korra went forward and hugged the smaller woman; she felt Tonraq's hand on her back, supportive and strong. Maybe he was the one she had gotten her strength from.
"Mom. Dad." Korra gently pulled away, stepping back to look at them. "I'll miss you."
Senna's voice almost broke, speaking for both parents. "We love you so much." It was true, but when she spoke it sounded like it wasn't enough. There was so much left unsaid.
Korra didn't answer. She knew if she said the same thing, she would cry. She hadn't cried in years, and she didn't want to start again now.
Her parents were the only ones who had ever told her that she was loved.
Korra mounted Naga, and cast one last glance back at her mother, her father, and her home. As she steered Naga and turned her back on them, she was acutely aware that she was leaving her past behind, and going forward to meet the future.
She loved them for letting her go.
Edit: I made some slight changes to this chapter to keep it canonically compliant with information revealed in the later episodes. "The Southern Lights" revealed that there was no Aurora Australis during Korra's childhood, so I had to take out my idea that she could have seen them with her parents. Also I read that Korra actually found Naga in the wilderness, instead of her being given as a gift as I'd supposed.