A/N: I thought the concept of this up late ages ago, but never found a good way to end it, but now Zutara month motivated and fuelled me, and I am proud to present: This! Featuring:
Katara'sActualSon!Aang, Zuko'sDaughter!Ty Lee, CoolAunt/Uncle!Sokki, and much more shenanigans, but ended up a little more serious yet fluffy, but still featuring all that. And it's all in a modern AU, because then I can.
The ages:
Katara, Azula: 24
Sokka, Suki: 25
Zuko: 26
Aang: 4
Ty Lee: 2
Iroh: somewhere in his 70s
Disclaimer: I do not own Avatar: The Last Airbender, if I did, I'd be American, male, or a multi-billion dollar television company.

"C'mon Katara, it'll be fun!" Sokka urged, setting down his coffee mug to put his arm around his sister's shoulders.

"You need to get out there again! Just because that asshat Jet left you-"

"I left him, Sokka," she interrupted him. "It's the other way round. I left him because I realised how crazy he is. He's a racist extremist, who was committing terroristic acts for extremist, racist reasons, just like you always told me!" She tightened her grip on the mug on the counter before her, looking over it to see her sister-in-law and her four-year-old son Aang playing a game on the carpet.

Sokka noisily took a sip form his coffee before continuing.

"Like I was saying, just because the guy who got you into this mess isn't with you anymore, and you and Haru didn't quite work out, doesn't mean you have to stay single and sulking forever!"

His sister gave him what he hoped was a hopeful look.

"Really? You think someone will want to get together with me, a single mom who got pregnant too early and ended up single because her boyfriend was a psychopath?"

Sokka grinned widely.

"Oh hell yeah! You're my awesome baby sister, who wouldn't wanna get with you?" He paused, suddenly remembering something. "Do you remember my buddy Zuko from my exchange year at Avatar Roku University?"

Katara frowned.

"The guy with the crazy hot sister and the scar?"

Sokka nodded, and patted her back.

"Exactly! Though his sister was crazy comma hot, not insanely hot. And don't mention the scar to him, he's very sensitive about that. Well, the two if us have been e-mailing a lot recently, and turns out, he recently moved here and shares a similar fate as you do. Crazy, right? So anyways, his girlfriend died, he was left a single dad, and now, a few years later after being finished with uni and being done with having to pay a lot of babysitters over the years, he's got a job as a lawyer here in Ba Sing Se and has temporarily moved in with his uncle - Iroh, swell guy, owns a tea shop somewhere around here," Sokka took a deep and obnoxiously loud sip from his cup, causing Katara to frown at him disapprovingly," - so that he can take care of his daughter while he's at work."

He glanced over at his sister, who was watching her son whilst absent-mindedly stirring her coffee, her spoon softly clanking against the inside of her cup. Sighing, Sokka put down his cup and waved a hand in front of his sister's face.

"Hellooo?!"

No reply. He tried again, flicking a finger against her cup's brim.

"Sis, were you even listening?"

The brunette's head snapped around, confusion flickering in her eyes.

"Wha- yeah, of course. Zuko, Iroh, daughter, here," she quickly recited.

Satisfied, Sokka smiled. Then, realising the delicacy of the task he had intended, his mind started pacing, making him feel as if his mind had left his body and was now running around the room in a frenzy.

"Sokka? Why are you looking at me as if I am a part of one of your crazy science projects?"

Said scientist blinked, shook his head to clear it and made a dramatic gesture.

"There's this friend of Zuko's - Well, an ex, to be precise - who is a therapist. And she also does therapy for single parents - and their kids - with bad experiences, so basically you two. There's a meeting next Wednesday, and I know Zuko already agreed because she's his friend and sometimes therapist, and I thought it's done good for him to see someone familiar, and you could use the support, maybe meet a nice guy, and just give it a try?"

The hopeful, pleading reflected in his cobalt blue eyes could have destroyed even Gran-Pakku, he reckoned. His sister gave him one look, sighed, and slumped down onto the counter.

"Alright. I'll do it."

Sokka raised his arms in victory, and almost cried out loud. Suki looked over at him, a little curious. He met his wife's gaze with a victorious smile and excitedly pointed to his sister, mouthing "She's going!" ecstatically. Suki chuckled and picked up her nephew, returning him to his mother.

"Here you go, Katara. Have your little whirlwind back."

Said nurse smiled a little drowsily and reached put towards the toddler. Her sister-in-law carefully placed him in her arms before leaning over and giving her husband a quick peck on the cheek.

That Wednesday
Katara looked around the small gym, in which parents and their children littered about, although less than she had primarily expected. The avid chatter and wails brought her back to a time long gone, when life has been simple, and all she'd had to worry about were grades and what she would be wearing that day.

The sound of a throat being awkwardly cleared behind her brought her back to reality.
She turned to see a face she knew too well from her brother's college photos - a face with blazing amber eyes, messy dark hair, high cheekbones, and of course, a harsh, comet-shaped, red scar over his left eye.
He looked her up and down, his expression going from worried to relieved as he did so.

"Hey. You're Katara, right? Sokka's sister, smart, maybe pretty, average height, with watery blue eyes? Honestly that maybe is an understatement though I should probably not say that out loud-"

He stopped mid-sentence, as if suddenly realising what he was saying, and awkwardly rubbed the back of his neck and seemed to suddenly find his shoe very interesting. Katara couldn't help but snort at the first description he gave her. It clearly stemmed from her no-good brother. The latter, well, it was flattering, at least.

"Yes, that would be me. Sokka's bossy little sister."

She laughed, and smiled at him. An insecure smile crept across his sharp features and he cleared his throat again.

"So uhh...Want to talk about hyperactive toddlers?"