Zuko was worried. Toph had told him he heard Katara crying in her room the last few nights since they got back from the Boiling Rock with her dad and Suki. He was split on whether to confront her himself and ask what's wrong, or send Toph to girl-talk with her.
"I'm not going in there," Toph said, picking at her nails. "She's all yours, Sparky. Good luck."
He wrinkled his nose at the nickname, but started in that direction with the help of Toph's firm pat on the back. He stopped a few steps away from her room. Toph was right, you could hear it halfway down the hall. Zuko was actually a little surprised Sokka or Aang hadn't been in there yet. Then again, Sokka had Suki and Aang.. well, he was just Aang.
He knocked lightly on the door and listened. He heard her sniffle a little, then there were some shuffling noises and her door creaked open slightly. She seemed a little surprised to see Zuko there of all people, judging by how wide her bloodshot eyes got. He put a hand on the door, for fear she would try to slam it in his face, but she didn't attempt to.
"Did you want something?" she asked, trying to keep her voice in check.
"Can we talk for a minute?"
Katara seemed to consider it for a second, then sighed and opened the door the rest of the way, Zuko closing it behind him as he entered. He took a seat on a chair near her bed while she climbed back into it and cuddled her pillow. When he looked down into his lap, she took the opportunity to wipe her eyes again.
"Look," he started, "I'm not exactly sure what's wrong, but-"
"Wrong?" she said, looking confused. "Who said there's something wrong?"
"Your eyes. You've been crying. The last few nights, according to Toph."
Katara narrowed her eyes. "I don't see how that's your business."
She stood from her bed and started toward the door, but Zuko was faster and moved to block it. "If you keep it bottled up inside, it'll hurt more, and I don't see you making an attempt to talk to someone else about it. Please, Katara, just talk to me. Did I do something?"
New tears sprang to life in her eyes and he winced, thinking maybe he did. She bit her lip for a moment, then yelled, "Yes! Yes, you did something, you idiot! I'm supposed to hate you! How am I supposed to keep doing that if you go out and rescue my only family? Tell me that! How come I can't hate you anymore?!"
By this time, her tears were dripping from her chin and she was pounding on Zuko's chest, presumably hoping to beat some answers out of him. Zuko was taken aback by her sudden outburst and seemed a little uncomfortable at first, then he slowly grabbed her shoulders and pulled her against his chest and just held her, rubbing her back gently as she cried into his shirt.
"I don't want you to hate me," he whispered into her soft hair. "All that I've done since I came here was try to prove myself. Not to Aang or Sokka or Toph, but to you. I wanted to prove myself to you, prove that I really have changed, and it was all because of you that I'm here."
She sniffled a little and pulled away so she could look into his eyes. "Really?"
A corner of his mouth lifted into a half-smile as he brushed his thumb across her cheek, wiping a tear away. "Everything you said to me in Ba Sing Se haunted me the entire time after that. I couldn't stop thinking of you- I mean, what you said. The way you so easily dropped your guard and offered to heal my scar. I was even surprised at how easy it was for me to drop mine as well. I couldn't even do that around my own girlfriend!"
That got a small laugh out of the waterbender, which made Zuko feel proud, like he was actually helping. His smile widened just a little. "What I'm trying to say is, even though we've fought in the past, you're probably the nicest person I've ever met. And a little kindness can go a long way."
Another tear rolled down Katara's cheek and Zuko brushed it away before she could. His hand remained on her face, though, and she found she liked its warmth. It wasn't quite as rough as she had thought it might be, and La forgive her, she had thought about it before. She stared up into his golden eyes, finding nothing but sincerity there. She realized that before, they had always been so closed off. That meant his guard was down. He trusted her that much.
"I- I never said thank you," she whispered. "You know, for saving my dad. And keeping Sokka safe."
"I owed you that much, at least," he replied softly. "After everything I'd done to you. You personally."
Just like that, they were back under Ba Sing Se in the green glow of the crystals that surrounded them. Only this time, there was no big explosion of rock or an Avatar or uncle to interrupt them. Katara reached up and lightly traced the bottom edge of his scar with her thumb. He closed his eyes to her cool touch. She was the only one he'd ever willingly let touch his scar.
"I wish I could've healed you anyway," she continued whispering, barely audible.
He opened his eyes and noticed her face seemed a little closer to his. She kept moving in until her lips brushed against his scar where her thumb had just been. His breath hitched in his throat as she kissed along the edge of it. When he remembered to exhale, she felt his hot breath on her throat. She pulled back to look into his eyes again, but he'd closed them again, and she noticed his breath was coming out in short puffs.
Again, he opened his eyes and found hers looking back. Her arms rested on his shoulders and her fingers played with his hair. He was suddenly nervous and excited at the same time, and that scared him. "Yeah?"
She moved in again slowly, still keeping eye contact with him. Her lips brushed against his and he moved forward slightly to catch them, but she pulled back just enough to keep her lips barely touching his. "I think I forgive you," she whispered before finally giving in and crushing her lips against his.
A whirlwind of passion was released between the two of them, something neither of them expected they had in them when he first knocked on her door. His hands held the back of her head as he backed her into her door, and her own arms were wrapped around his neck tightly. Of all the people, she thought distantly before her mind was consumed with Zuko's warmth as well.
Outside, there was a small snicker and light footsteps fading down the hall as Toph went back to her room. "I guess she doesn't hate him after all."