Zuko didn't sleep for the first couple days after he joined the Avatar.

It was hard to keep his eyes open, but given the way the Waterbender looked at him when he was awake – with hostility so intense it almost burned – he wouldn't have put it past her to try to drown him in his sleep. And that was without taking the Water Tribe boy with the boomerang into account, who even more constantly looked like he wanted to take off Zuko's head and possibly more.

So he didn't really feel comfortable closing his eyes and relaxing. He kept his eyes open and stared into the fire, feeling it pulse and fade with a heartbeat of its own, trying not to let it lull him into sleep.

It was interesting, besides, watching all of them sleep. It made him think about how young they really were, especially the Avatar. Especially Aang, he corrected himself. The others didn't seem to like it when he didn't use the – Aang's name, even if it felt strange to do so after hunting rumors of him for three years.

Aang snored when he slept. He tossed and turned, limbs flopping around him like wet noodles, though he didn't seem troubled by bad dreams. Sometimes he muttered in his sleep, but never loudly enough to make out words.

All of them snored, though Sokka snored the loudest. Toph moved the least (she slept like a rock, Zuko thought with faint amusement). Katara sometimes hummed, melodies he didn't know, probably Water Tribe lullabies. Who knew what girls dreamed about? Mai never talked about it.

(And there was his other problem: Mai. He tried often and hard not to think of her, but especially when he was watching Katara sleep, she always seemed to come up.)

Most often, when that happened, Zuko curled his arms around his knees, pulled them to his chest and tried to follow different thoughts, drawing nearer to the fire and trying to take from its familiarity some comfort, some company.

Tonight, though, was different. Tonight he was just watching Aang, because the young Airbender was having a nightmare of some kind, his tossing taking on a kind of desperation, limbs pulled tightly into his chest. Zuko got up slowly, looking away from the pulsing heart of the fire and the bare warmth it offered, and moved to Aang's side, reaching out slowly to wake him, excuses prepared for why he was awake, why he was waking the Avatar (in case the Waterbending girl objected, which she almost certainly would), when Aang flopped to his stomach, gasped, shuddered, and fell still.

Zuko blinked, his eyes widening. There was a livid star in the center of Aang's back, made of whorled scar tissue. He swallowed.

He knew what that glow meant, knew it meant death for everyone in the room, death or at least pain. Zuko stared, helpless, some piece of him wondering if this was his punishment for betraying his uncle.

And then the blue lightning struck and the Avatar writhed in midair, dancing like a puppet on strings, and fell.

It was over.

Zuko drew back and sat on his heels. He hadn't thought about that. Or he had, but not – really. It looked awful. Ugly.

He thought about the Avatar – about Aang as he'd seen him these past few days. Laughing and grinning and darting about without a care in the world, just a kid, really; a kid without a clue, but a kid nonetheless. He was…sweet. Cute, even.

This scar didn't belong on that kid. Avatar or not.

Zuko felt a low kind of sick guilt settling in his stomach. "I'm sorry," he said, quietly, and moved back another foot, sat down and crossed his legs and just looked at the scar that his sister's lightning had left. That his well timed betrayal had left.

Aang would have that scar for the rest of his life. He would probably show it off, if they came out of this alive. See? This is where Princess Azula almost killed me. But I got her in the end. Zuko rubbed his face, feeling suddenly exhausted.

I haven't slept for two days. It's making me melancholy. That's all.

The speed with which Aang's eyes opened startled him. "Zuko?" He nearly jumped, and just managed not to. "What are you doing up?"

"I couldn't sleep," he lied. Didn't want to sleep. Didn't trust his former enemies enough to let himself sleep. "Go back to bed. I'm just thinking."

"Is something bothering you? Whenever I can't sleep it's because something's bothering me and sometimes talking helps-"

A kid without a clue. "No. I'm fine."

"Do you ever sleep at all?" Aang asked, eyes wide and innocent, head tilted plaintively to the side.

"Of course I sleep. Everybody sleeps," Zuko said, defensively.

"Cause the last couple times I woke up you were awake too. So I was just kind of wondering-"

"I'm fine," Zuko said more sharply. "I mean it. I just – don't sleep very much, that's all. Why are you awake, anyway?"

Aang shrugged, and smiled ruefully. "Oh, it's nothing, really. My back's just bothering me a little. It does, sometimes."

"Your – scar?"

"Where Azula got me, yeah." Aang seemed utterly unselfconscious, saying that. And worse, he seemed completely unaccusatory. Like it wasn't Zuko's fault. He felt like cringing. "It's just a little sore sometimes. Like a tight feeling in my back."

Zuko hesitated, and on an impulse, stretched his hand out toward Aang's back. "Here," he said, and Aang flinched away. Zuko pulled back quickly. It stung, but he shouldn't have been surprised. Of course Aang would expect the worst. What reason did he have to think any better?

"What is it?"

Zuko shrugged. "Never mind. It was just something my - mother used to do."

Aang blinked. "You have a mother? No one ever talks about the Fire Lady."

Zuko felt his mouth tighten and turned his back. "Had. She's been gone a long time."

"Oh," Aang said, and he sounded chastised, ashamed. Zuko knew that was wrong – he was the one who should have been ashamed. What had he been thinking? Of course the Avatar wouldn't want anything from him. Other than training so that he could kill the Fire Lord. "I'm sorry."

"You weren't even conscious. How is it your fault?" Zuko snapped. Aang paused.

"Go on," he said, suddenly. "Go ahead, whatever you were going to do. It's okay." Zuko turned in surprise, and saw Aang smile. "I trust you."

"It's just a little thing," Zuko said, cheeks burning. "I don't even know if it'll help. Or if I remember how it works." He reached out again, and laid one palm over the star-shaped lightning scar. "She used to…when Azula and I had been roughhousing and I got hurt, she used to do this."

"What was her name?" Aang asked, in a weirdly quiet voice, and Zuko hesitated.

"Ursa," he answered, after several moments, and began to heat his hand, very slightly, imagining the warmth from his hand sinking into Aang's body, loosening muscle, untangling the knots that were causing him pain. He could feel the heat radiate out from his hand, and felt Aang sigh, his shoulders sinking down.

"That actually feels…really good."

Zuko blinked. "It's working?"

"I think so," Aang said, rocking forward slightly. "It definitely feels nice. She used to do this for you?"

Zuko felt a pang. "Yeah. She had a name for it, I don't remember what." There was a long silence. Zuko listened to Aang breathe, feeling himself soothed by the heat radiating up his own arm and into his chest, loosening the fist around his heart.

"You don't have to feel guilty, you know," Aang said, suddenly, quietly. "About what happened. It wasn't you."

"I don't feel guilty," Zuko lied. You forgive too easily. "It was my sister. Like it always is."

"All right," Aang said, surprisingly mildly. "You don't feel guilty. I just thought you should know that I don't blame you." Zuko pulled his hands away, knowing that the tension he was beginning to feel would translate into the Avatar's body. Aang flopped back, grinning. "Thanks, that was great. I feel a lot better. We should start calling you 'Zuko Magic-Hands.'"

"No thanks." Zuko turned his head away. "You don't blame me, maybe."

Aang looked up, his eyes wide and surprisingly perceptive. "Is that why you're not sleeping? Because you think we're going to do something to you or something?" Then he smiled, the seriousness vanishing. "I know Toph's scary, but sheesh."

Katara said she'd kill me. "Just go back to sleep, Aang."

"Is this about Sokka? Cause he's really not as mean as he looks. And he'll get over it. I mean, he gets over everything."

Zuko sat down and stared at the fire, trying to feel its pulse and forget all other things. Breathe. In, out, in…

"Did Katara say something?" Aang was sitting next to him, now, face furrowed in worry.

"Katara says a lot of things," Zuko muttered sourly.

"Most of them she doesn't mean," Aang said, helpfully, his upturned, open, child's face furrowed with worry. "She's not going to attack you, or something." Aang paused. "Is she? Did she say something that made you think-" His eyes widened. "Did she threaten you?"

"You're going to get all tense again," Zuko said tightly. "Go back to sleep."

"So what if I do? You can just do the fancy hand trick again. What'd she say? Maybe I can help."

Zuko clenched his fists. "She hates me. You can't change that and I don't want you to try. It's my problem and you don't need to get in an argument with your girlfriend over it." Aang turned bright pink, and Zuko got up quickly and turned to walk away.

"Wait," Aang said. "Will you – can I at least talk to her? Just a little? I think I might be able to help. You can't just keep – not sleeping." He hesitated. "Besides, you helped me tonight. Really helped me. Katara just – doesn't get some things, that's all."

Zuko sighed. He was tired. He wanted to trust everybody, but…

I'll make sure your destiny ends, right then and there. Permanently.

She'd almost looked like his sister, saying that.

"No," he said, firmly. "I'll work this out on my own." He put his fist to his palm, and bowed. "—but – thank you, Aang."

The Avatar sighed. He looked so disappointed that Zuko almost felt bad for telling him not to interfere, watching Aang scuff his feet in the dirt, but finally he looked up. "All right," he said, sounding newly determined. "I won't say anything. But if I do that, then I'm taking the rest of the night's watch, and you can go sleep. And I promise if anyone tries to stick your head in a bucket of water, I'll stop them. Is that fair?"

Zuko looked down at the Avatar. Just a kid. But a pretty smart, insightful one, too. Maybe the world wasn't quite so doomed. He couldn't remove the old scar, but at least he could make sure there weren't any new ones.

"Well?" Aang demanded. Zuko sighed.

"Fine," he said, at last, and looked directly at Aang. "I trust you."

Aang nodded, and then grinned and darted forward, flinging his arms around Zuko and giving him a quick, tight hug. "Goodnight, Zuko," he said, face mushed against his chest. "Sleep tight. Don't let the bedbugs bite."

Then he detached, sitting down with his back to the fire and his legs crossed, looking out at the darkness. Zuko stared at the scar a moment longer, then sighed, turned his back, and trudged to where his bedroll lay a safe distance from the others.

Suddenly exhausted, he dropped to the ground and pressed his face into the pillow.

He slept soundly, without dreams, and when he woke, the A- Aang's head was pillowed on his shoulder, snoring softly, with a lemur curled up on Zuko's chest. The sun was just beginning to rise, and no one else was awake. Zuko closed his eyes and smiled.