Disclaimer: I do not own Avatar: the Last Airbender, it's owned by its creators Michael Dante DiMartino & Bryan Konietzko and Nickelodeon.
Zuko sent a messenger hawk to Aang and a separate one to Sokka. He hoped that if the hawk didn't reach Aang that Sokka would. Then he returned to the Spirit Oasis and waited. He hoped Katara would return before Aang or Sokka would get the messenger hawk.
Meanwhile, Katara cleared the Earth chakra and faced her fears: including fighting Zuko, not being able to save Aang, being beaten by Ty Lee, who took away her bending, and not being able to save Zuko.
She cleared the Water chakra and the guilt and blame she placed on herself for putting them danger when she stole that Waterbending Scroll, when they got caught by that scheme she tried to pull off with Toph, for bloodbending the innocent Southern Raider captain.
She cleared the Fire chakra and faced the shame she felt for becoming a bloodbender, and taking her anger about loosing her mother out on Zuko.
She also cleared the Air chakra and dealt with the grief of loosing her mother as she touched her necklace and realized she still had her father and brother and that she was capable of love in all its forms, and even though they broke up she still loved Aang.
She cleared the Sound chakra, and she faced the lie that she often told herself that she wasn't needed by her father.
She cleared the Light chakra easily, remembering the Morishitas and she realized that all the elements are connected.
"This is the last chakra left. It's the one Aang couldn't master. I wonder why," said Katara. Before Katara could go back to meditating, an unexpected figure appeared before her. She said in a surprised tone, "General Iroh."
"Hello Katara. My nephew contacted Sokka. He also contacted Aang, but Aang felt that if I could reach you that would be enough. I heard you wondering about that last chakra," said Iroh.
"So you know what it is?" Katara asked curiously.
"Yes, but I'm not sure it will give you what your looking for," Iroh replied.
Katara sighed, "It's just that Yue said that I need to find balance within myself in order to get my bending back."
"I see," said Iroh. He thought for a moment and then continued, "You have to let go of your earthly attachments."
"Oh," said Katara surprised. She thought about what attached her to earth. She thought of Aang and realized that he didn't need her. She meditated and walked into the hands of a giant version of herself and accessed the pure cosmic energy. After she obtained access, she realized how to get back and she opened her eyes. She said, "Thanks for the advice."
Iroh realized that Katara didn't need help anymore so he returned to the physical world.
Katara went to the pond where she had been pulled into. She swam through and came out of the pond. She discovered she didn't need to hold her breath as she swam. After what seemed like hours she surfaced.
Stay tuned...