My crossover choice was Firefly, as I planned to do a fic like this anyway! Only basic knowledge of Firefly necessary, I'll explain anything you don't know :)

Chaos reigned on Serenity as Suki raced up to the bridge to find Zuko. They had managed to just escape the Reavers, but the doctor, Katara, was unaccounted for, as well as the shuttle that Mai did not reside in. Suki did not think it was a coincidence. As she approached the bridge, she heard her husband arguing with the captain.

"What do you mean the other shuttle is missing?"

Suki burst in as Sokka got to his feet. "I mean just that, Cap! The shuttle launched just before we did!"

Zuko leaned over the controls. "Without alerting us?! Who took it?!"

Suki stepped forward. "I may be able to answer that, Captain."

Zuko whirled to face her. "Who took my shuttle, Suki?"

"I think Katara may have, sir."

Zuko paled considerably. Sokka gaped at his wife, then sunk into his seat. "Katara..... Katara's out there... with Reavers?"

Suki nodded gravely. Zuko continued to stare at her. She touched his shoulder. "Are you okay, Zuko?"

He didn't answer. Suki started to ask again, but Zuko brushed past her and headed down to the cargo bay. He had to see someone. Someone who was supposed to watch her. He stormed into the cargo bay, where Toph tried to comfort a confused Aang, and Jet cleaned one of his guns. Jet looked up as Zuko came down the stairs. He smiled. "Hey, Captain. What can I-" Zuko cut him off by slamming him into the wall. "Wha-what the hell, Cap?!"

Zuko growled and pushed him harder into the wall. "You were supposed to watch her!" He could hear Toph stand, Mai opening her shuttle door and Suki running across the cat walk above him.

Jet tried to push Zuko's forearm off his chest. "I tried to stop her! She pushed me out of the way!"

"You weigh 50 more pounds than she does!"

"She's a waterbender from Tribe! I'm a pushover compared to her!"

"When I get done with you, you're gonna wish that's all you are!"

"Captain!"

Zuko turned his head and glared at Sokka. "What?!?"

Sokka gulped and took a step back, even though he was on the opposite cat walk. "The shuttle's coming in, sir. Katara just waved us. She's fine."

Zuko dropped Jet and faced Sokka. "She's fine?"

Sokka shrugged. "Shaken up and in the company of five of the villagers, but yeah, she's fine."

Zuko paused a moment, then raced up the stairs at the sound of the shuttle docking. Suki followed him. The door opened and five people, some blood soaked with their clothing torn, rushed out of the shuttle. Zuko's thoughts scattered as Suki gathered the people and led them down the stairs. 'Where is she? What happened? How could she be so stupid? Is she all right? Please, let her be-'

The subject of his thoughts stepped out of the shuttle, brushed her hair back and gave him a tired smile. "Hey, Zuko. Sorry I-"

At the sound of her voice, Zuko grabbed her by the arm and dragged her down the cat walk and into the hall. He could hear her protesting, fighting to get out of his strong hold, but he didn't care. Her arm was in his hand, she was there. She wasn't dead. She was there.

Zuko finally stopped outside of the infirmary. He grabbed her other arm and quickly scanned her over for injuries. He was rather rudely interrupted by a slap to the face. He released her and held a hand to his face.

"What in the gorram 'verse do you think you're playing at?!?!" Katara stood there glaring at him, hands on her hips.

Zuko glared back at her. "I was making sure you were okay. What were you doing out there? Trying to get yourself raped and eaten?"

Katara looked taken aback. "I was just trying to help-"

Zuko continued. "You could have been killed, do you get that? And it wouldn't have been painless or merciful. You would have died and we'd be left without a shuttle, without a doctor! And then what? You'd be dead, and I'd-" He stopped, eyes widening as if he had said too much.

Katara lowered her arms. "And you'd what, Zuko?"

Zuko stared at her. Her brown hair was a mess, her clothes were torn and blood stained, she was covered in a light layer of dirt and she looked on the edge of exhaustion. It didn't matter. All he could think about was how glad he was that he could see her beautiful blue eyes, her just as beautiful face. He was so glad she was alive.

Katara opened her mouth to ask again, and ended up gasping as Zuko pulled her against him into a tight embrace. She stood still, letting the trembling man hold her. Slowly, she returned the embrace, placing her hands on his shoulder blades. "Zuko..."

He held her tighter. "Wuh de tyen ah, Katara, if you had died, I don't know what I'd have done."

Tears welled up in Katara's eyes. She smiled and placed her head on his shoulder. "I thought you hated me, Zuko."

She felt him shake his head against her shoulder. "No, of course not. Why would I?"

"Well, you've always treated me like luh-suh."

Zuko chuckled and pulled out of the hug, smiling. "Only because I initially wanted to push you away. I'm scarred in more places than my face, Katara."

Katara smiled up at him. "I'm good with scars, Captain."

Zuko pulled her close again. "How about emotional baggage?"

Katara mockingly looked deep in thought. "Hmm... I think I can help you with that, too, Captain."

The captain smiled and leaned down to kiss her. "I'd like that, Doctor."

Chinese (Written pronunciation-wise):
Wuh de tyen ah- Dear God in Heaven Luh-suh- Garbage

I'm going to be double checking the first translation :)

CROSSOVER DONE! Hope you like it :)