He tossed and turned for hours, trying to to fall asleep with no success. There was too much to think about - the comet, firebending training, his father's plans for the Earth Kingdom. Normally he wasn't one to stress every little thing, but there was a lot riding on his shoulders as the one who had to teach the Avatar firebending in such a short time.

He sat up. There was no point in trying to sleep - it wasn't going to happen. The full moon streamed through his open window. Maybe a walk would clear his head, he thought, slipping out of bed and heading for the door.

He padded through the halls barefoot and shirtless, making no sound whatsoever, pretending, for a moment, that the Blue Spirit was on the prowl once again. Once he reached the courtyard, he headed toward the fountain, only to pause in the shadows as he realized someone was already there.

Katara sat on the edge of the fountain, twisting a thin stream of water between her fingers. Zuko hesitated, not wanting to interrupt her, but she looked up and caught sight of him hovering.

"Zuko?" she said, peering into the shadows. He walked out and joined her at the fountain, sitting on the ground with his back to the base. "What are you doing up?" she asked, looking down at him with concern.

"Couldn't sleep," he said, leaning back against the cool stone and closing his heavy eyes, letting the soft noise of the fountain wash over him.

"Any particular reason for that?" Katara asked gently. Zuko sighed.

"Aang's firebending, mostly," he confessed. "I'm worried that he'll - I don't know, forget everything when it comes time to fight - or he won't be able to deal with something because I haven't taught him well enough. I'm also worried about his refusal to kill - that's not the way wars are won."

"I've been thinking about that, too," Katara admitted. "But as far as his firebending goes, I don't think you have anything to worry about. You're a good teacher and he's a quick learner." She smiled a little.

"What about you?" Zuko asked, glancing up at her. "Why are you still awake?"

"It's a full moon," she explained, gesturing at the sky. "I can't sleep - the energy rush is too much."

"Right, it boosts your waterbending," he remembered. Then a thought occurred to him. "Wait, every full moon you can't sleep?" Katara nodded with a slightly bitter smile.

"That's terrible," Zuko said, frowning.

"That's being a waterbender," she shrugged. "What about you? You're up with the sun every morning, no matter what."

"That's different."

"Is it?" She raised an eyebrow.

"It's a habit, not because of my bending."

"I seem to remember a certain firebender declaring that he rose with the sun and that it gave him power."

Zuko scowled at her grinning face and leaned back against the fountain again. "Whatever you say," he sighed.

"You know I'm right," she smirked, then yawned. He looked up at her, somewhat surprised.

"I thought you weren't tired," he said.

"I wasn't," she replied, yawning again.

"I'm that boring?"

"Apparently," she laughed. "Really, it's just nice to have someone to talk to. It's distracting me from the pull of the water."

"Glad I could help," said Zuko, and meant it. "You do too much to go without sleep so often."

"What's that supposed to mean?" Katara asked, frowning. Zuko paused, trying to think of a way to put it that wouldn't sound stupid.

"You're like everyone's mother," he said finally. "You're always taking care of everyone in the group before yourself. And you're so good at it - I would never have guessed you'd been going a full night without sleep every full moon."

Katara shrugged, looking slightly uncomfortable. "I'm used to it." She yawned again. "And I don't mind it much." She slid down off the edge of the fountain and sat with her back to the base, her arm touching his. "So talking to someone helps you sleep?" Zuko confirmed.

"Looks like it," Katara nodded.

"I'll keep talking, then. Anything you want me to talk about?"

"How…" She yawned. "How did you get that scar? I've always wondered."

He was struck silent for a moment; he wasn't quite sure where to begin - or if he even wanted to tell her. But she had asked, and he's promised to talk to her. Besides, she'd once offered to heal his scar with her precious spirit water; she deserved to know the story behind it.

"I was thirteen," he started. "I'd been begging for weeks and weeks to be allowed to sit in one of my - one of the Fire Lord's war councils. My uncle finally let me go in with him to one of them, but before we went in, Uncle made me promise not to speak out. I should have listened.

"They were discussing the Earth Kingdom, and a heavily armed battalion that was proving itself a nuisance. One of the generals suggested using a division that was all new recruits as bait in an ambush.

"That's when I spoke out. I called the plan a betrayal of our soldiers and basically said that at thirteen I knew better than he did. My father was not pleased, and told me that this was a grave offense and would require an Agni Kai - a duel of honor - to settle. I accepted, confident that I could take the old general, and the duel was set for the following day.

"But when I stepped into the arena, I wasn't facing the general. I was facing my father." He was speaking coldly, in a detached tone, watching it in his mind again as if at a distance. Katara watched him with concern, no longer sleepy. He took a breath, then went on.

"I had insulted my father's honor by calling one of his generals a fool in his own war council, so the Agni Kai would be fought against him. I was no match for my father - I'm still no match for my father - so I fell to my knees and begged for mercy.

"He called me weak and ordered me to fight, but I refused - I couldn't fight my own father! So he struck my face and banished me. The only way I could return home was if I captured the Avatar. Then I would regain my lost honor - and my father's respect." He scowled down at the cracked stones of the courtyard, not wanting to see Katara's look of pity.

"Hey," she said softly. "Look at me." He reluctantly dragged his eyes up to hers. She waited until he was looking her in the face, then said, "I think you're very brave, Zuko." There was no pity in her eyes, only a kind of respect, and then they suddenly flashed with anger. "How dare he do that to you? If Aang can't deal with the Fire Lord, you and I are going to team up and take him down ourselves."

"We are a pretty good team," Zuko said, not really knowing what else to say. He was strangely touched by her instant defense. And with Katara, it wasn't just talk. She actually meant it.

"And I'll have your back. No matter what," she added. He glanced over at her.

"You have Aang and Sokka to look after," he said, not wanting to sound ungrateful but also wondering why she was saying this.

"Yeah. And now you're on that list," she said. "Besides, we're the responsible ones in this group. We should have each other's backs."

"Well, when you put it like that…" Zuko smiled. "And, since I'm responsible for you now, I say you should go to bed."

"Keep talking, I'll probably fall asleep," said Katara, leaning her head on his shoulder. "Tell me about things you do in the Fire Nation. What's it like to live there? I mean, we did for a while, but we were in caves and stuff."

"Well, we have some pretty wild festivals on the summer solstice…"