A/N: This fic was written for the capslock_zutara LJ community's "Seven Days of Capstara" Week. Enjoy!
"I'm so tired of this!" Aang crowed to no one in particular and sat down in a huff, next to Toph in the circle around the campfire. The rest of the kids looked up, and Katara—on motherly autopilot—began preparing him a bowl of congee.
"…So tired of what?" Toph asked, slurping the contents of her bowl.
"Of this firebending training! It never ends! We were up at nine this morning, and I get one ten-minute break for lunch, and then we won't be done until five in the evening! I'm so tired of this already!" He threw his arms up, exasperated, but put them down quickly to receive his bowl of rice porridge.
"That's what training is, Aang; it's demanding for a reason." Toph finished her bowl and set it down in her lap. "You have how many days until Sozin's Comet arrives? You have to squeeze years' worth of training into a couple of weeks. No one said it would be easy." She wagged a finger.
"But Zuko is crazy! He never stops!" He shoveled porridge into his mouth with frustration and spoke over it. "I'm beginning to wonder if he really is the right firebending teacher for me. There's got to be someone who's less of a military instructor about it, and is calm when you screw something up, and even goes the extra mile to make it—"
"—Fun?" The group looked up again, this time at Zuko's sudden interruption as he stood over the circle. His face had puckered into an angry frown at overhearing the Avatar's complaints. "You think firebending training is supposed to be fun? I have two words for you, Aang, and you're not going to like them, but they're the reason why I'm pushing you so ha—"
"SOZIN'S COMET, I know," Aang replied impatiently, rolling his eyes as Toph and Sokka snickered to themselves. Katara gave all three of them a stern look.
Zuko's frown intensified. "I was going to say Fire Lord," he punctuated irritably. "Either way, you're not ready to face him yet, and trust me when I say that I'm not going to stop training you until you are. Whining about it isn't going to help things." He stalked to another side of the circle spread out around the cooking pot and sat down, crossing his legs. He held out his hand to receive his bowl of congee a moment later.
Toph smirked to herself before speaking. "Yeah, Aang, you really don't have it that hard, you know," she chortled. "You think you have it difficult just working from nine to five, but Zuko's day doesn't end so early. He's usually working up late into the night, too." Both firebender and waterbender heads snapped to attention at her words.
"…Why not?" Aang turned to Zuko, questioningly. "What do you work on after you're done training me?" His firebending teacher reddened across the bridge of his nose.
Katara began coughing loudly on her own rice porridge, prompting Haru next to her to pat her on the back. "Katara, are you okay?" She nodded, her eyes tearing a bit.
"She's fine," Toph insisted, knowing an attempt to distract when she heard one. "She and Zuko are usually up late together."
Now Aang turned to Katara, his expression slightly wounded. "You're up late at night with Zuko?...Doing what?"
She opened her mouth to reply, somewhat uncertain, before Zuko spoke up on her behalf. "—Sparring. Katara likes to practice her bending at night, when it's the strongest…and I'm usually the only one who's up so late for her to practice, with." He met the waterbender's eyes apprehensively.
"And it's very…loud…practice," Toph contributed. She smirked again, feeling their hearts hammering through the stone floor beneath her.
"Oh." Aang seemed completely placated by the explanation. "I can understand that. Wow, Zuko, you must be more tired than I am, then, if you're working both day and night." Zuko nodded stiffly. "If you ever want to cut our practice short, though, so you can get more sparring in with Katara, I'd be okay with that. I know working hard is just as important to her as it is to you." He smiled. "In fact, I think you both have an extremely strong work ethic, in common!"
Waterbender and firebender both looked at him, blinking.
"So why don't you guys go practice somewhere right now? I know it's not nighttime when you're stronger, Katara, but it might be useful to practice with Zuko when he's the stronger one sometimes. Right?"
Cricket-wasps could have chirped then and been heard. Finally in the stretch of the awkward silence, Zuko turned to her and shrugged.
"Katara? How about it…do you feel like practicing right now with me?" He fixed his gaze on her intently.
Something like a hint of a smile appeared at the corners of her lips. She got to her feet. "Sure! A—a change of schedule would be…challenging, wouldn' t it?"
"I won't go easy on you," he warned her, lowering his voice as he stood as well, and Katara appeared to tremble a bit—but not, Toph noticed, from fear.
"Race you there," Katara sang out, and took off running toward the eastern wing of the temple, Zuko suddenly hot on her heels.
Aang grinned into his porridge. "Ahh, now I can finally have a break. That was a great idea of mine, if I do say so myself!"
Toph smacked her forehead.