Okay, so this is a 'what if' story. It's been bugging my head for... SO long, and I think it's finally time to put it on paper (or in this case, the internet).

Summary: What if Zuko was able to capture Aang in the end of Book 2? And what if, to get him back, Katara, Sokka, and Toph have to ask for the assistance of Yue's younger sister? Who knew a single moment could change the course of history?

He could almost feel it; Aang could almost reach the Avatar State. He felt himself rising. Almost... there...

Back on the ground, Azula was about to strike Aang with a lightning bolt, but a hand on her wrist stopped her.

"No." Zuko told her. "Not yet. We could still bring him to the Fire Nation." Doing a quick roundhouse kick, Zuko made blazing arc, momentarily distracting Katara and the Dai Li agents. Seeing what her brother was doing, she quickly grabbed Aang and ran out of the cave, Zuko following shortly after.

That left Katara and the Dai Li.

She immediately created a huge wave, effectively scattering the Dai Li. She then ran out to look for the Fire siblings, but she was too late.

I'm so sorry Aang, she thought, while a few tears made their way down her cheeks.

"Katara!" Sokka yelled, running towards her. Noticing the tears and the sad expression on his sister's face, he asked, "Hey, what's wrong? Where's Aang?"

Katara collapsed into a fit of sobs, burying her head in Sokka's chest.

"They — They took him, Sokka. I'm so s-sorry." She cried even louder. Sokka's heart was breaking, he knew how much the young airbender meant to his sister, but he was also infuriated at the fact that Aang was captured by Zuko and Azula.

"Hey, shh, it's okay. It isn't your fault." He said, trying to comfort Katara.

"But, I wasn't there to protect him. I was more focused on the Dai Li! I—I let him be taken away. It was all my fault." Katara sobbed. Sokka just held her.

"Hey, you idiots! Hop on!" Toph's voice was loud and clear. The siblings climbed aboard Appa, melancholic looks on their faces.

As the first few minutes passed, Toph noticed that the three people riding with her were insanely quiet. So she decided to do something about it.

"Why are you all so quiet? Twinkletoes isn't even moving."

"I'm so, so sorry, Toph." Katara choked out, erupting into another fit of sobs.

"What are you sorry about? You didn't do anything... yet. I don't see why you should be apologizing." Toph said, completely and utterly confused right now. Just what was going on with her friends?

"Haven't you noticed something out of the usual?" Sokka asked her.

Toph shook her head. "No, not really... Except for the fact that Twinkletoes isn't moving at all, everything's fine."

Sokka didn't know how to tell her, so he broke it down for her gently. "Toph, the reason why... Aang isn't moving... is because he's... not here."

"Wha—Why? How? Is this why Katara was apologizing?" Toph said, eyes wide in disbelief.

"Yes, it is. And... Zuko and Azula... they..." He trailed off, knowing that Toph can figure it out by herself.

"They took him." It wasn't a question, it was a statement.

"I'm sorry." Katara told her again.

"Your apologies aren't going to bring him back!" Toph snapped.

"They were too much for me to handle! I couldn't take them all." She replied.

Toph was about to retort, but Sokka started talking.

"I think I may know someone who could help us bring Aang back."

This sparked the interest of the two — previously bickering — girls.

"Who?" They asked in unison.

"Back in the Northern Water Tribe, when Yue and I were still dating, she told me about her sister." Sokka explained.

"Yue had a sister?" Katara asked.

"Yeah, she just didn't want to be in the spotlight, so no-one really knows her that much." He continued, "Yue said her sister's name is Aria. She's the same age as I am, and, according to Yue, she was an awesome waterbender."

"Maybe we could become friends!" Katara beamed. Toph huffed.

"Anyways, I was thinking that maybe we could recruit her, and maybe she could help us to find Aang and bring him back." Sokka finished.

"That's a pretty good idea." Katara said.

"So... That means we're going to the Northern Water Tribe now?" Toph asked.

"Yes, we are. But, we have to get there as soon as possible. The faster we get there, the faster we could get Aang back." He turned to the bison, "You ready Appa?"

Appa made a noise of affirmation.

"Okay then! Yipyip!"

And so began their journey to the Northern Water Tribe.

After a few days, they finally reached their destination.

"How can you g-guys stand it here? It's so c-cold!" Toph shivered, hugging herself tighter.

"It's natural for us, I guess." Sokka answered her. They walked towards the Chief palace in silence for the next couple of minutes.

Chief Arnook greeted them warmly. "Sokka! Katara! How are you all? I see you've brought an earthbender with you."

Katara nodded. "This is Toph. Toph, this is Chief Arnook, chief of the Northern Water Tribe."

"N-Nice to meet you Old Man!" Toph said, still shivering from the cold. Chief Arnook laughed.

"I'm not that old."

"We come bearing bad news, Chief. Aang has been captured by Prince Zuko and Princess Azula." Sokka said.

"Oh no, that's horrible!" Arnook replied, a horrified expression on his face.

"We were wondering if your daughter, Aria, could help us in bringing him back." Katara told him.

"Of course, of course! Anything for the Avatar and his friends." He motioned for the threesome to enter the palace. "Please, come in while I call for her."

They came inside the enormous palace, and were immediately greeted by a pretty brunette with eyes the color of the sea.

"Aria! I was just about to call for you." The Chief said. "These are the friends of Avatar Aang. Katara, Sokka, and Toph." He pointed to them while their names were called.

Aria smiled. "Hello, it's nice to meet you. I'm Aria." She then narrowed her eyes. "Wait, if the Avatar is your friend, then shouldn't he be with you?"

Sokka shook his head. "No, unfortunately, he was captured by Zuko and Azula, royalty of the Fire Nation."

"That's exactly why they came here, Aria." Arnook explained. "They need you to come and help them in bringing him back."

She looked hesitant. "I—I don't know, Father. I mean, I'm not the best waterbender here, and I... I just don't know."

"Please, Aria." Katara begged. "I'm the reason why Aang was captured, and I really want to make things right. And the only way for me to do this is if you help us. Please, Aria, I'm begging you."

She still looked hesitant, but nodded nonetheless. "Okay, fine. I'll help you."

"Thank you so much!" Katara smiled and enveloped the older girl in a hug which was returned almost immediately.

"Give me half an hour to get ready, and I'll be ready to go, okay?" She told all of them, to which the four people in the room nodded.

Half an hour later, everybody was set to go.

Aria had her pack with her, which consists of a small bag of money, her water skin, and a spare shirt.

"Good luck on your journey!" Arnook said.

"Thanks, Chief!" Sokka replied.

Aria hugged her father one last time. "Goodbye, Father."

"Be careful."

"I will."

She climbed aboard Appa, and Sokka yelled, "Yipyip!"

"So, tell us about yourself." Katara said.

Aria shrugged, "There's really not that much to tell. I grew up in the Northern Water Tribe, learned waterbending all by myself, since the teachers there wouldn't teach 'girlies'. I didn't want to be known as the 'Other Princess', I wanted to make a name for myself. So, I didn't expose myself as much as Yue did, I just stayed in the background.

"When you guys came and Pakku taught Katara, I was finally able to get proper training. After the battle against the Fire Nation and my sister sacrificed her life to become the moon spirit, I lived a quiet life. That is, until you guys came today, and now, here I am." She turned to Sokka. "So, where are we going to now?"

Sokka turns around to face her, and said, "To the Fire Nation."