Zuko gaped down in astonishment at the girl tangled up in his fishing net. She was struggling to escape and making terrifying screeching sounds, but what was most odd about her was that her lower half was comprised of a tail.
A mermaid. He’d caught a mermaid.
And she was not happy to have been caught.
He quickly pulled out his knife and crouched down, cutting away the net. He couldn't really afford to get a new one, but he knew what his uncle would say; that he shouldn't let someone suffer when he had the power to help.
The coarse netting frayed beneath his blade then snapped, and he worked to rip it further. The mermaid was still struggling, and now that her bonds were loosened it actually did something. Her tail thrashed about, knocking into him and sending him sprawling onto the deck. At this point the screeching had been replaced by pained gasping noises.
Zuko surged up and straddled her tail, pinning it in place and returning to his task of cutting her loose. But he wasn't making fast enough progress. Panicked blue eyes met his own and held for a few moments before the gasping noises stopped and her body went limp beneath him, gills fluttering uselessly.
Zuko's eyes widened. No. No! He continued to cut the net away, nicking himself several times in his desperation. The mermaid’s eyes remained open but had rolled back, eyelids fluttering weakly. Her gills were barely moving now and he couldn't tell if she was breathing.
Just as he finished cutting her loose, her eyes shot open and she started to scream in agony. Zuko flinched back, but the scream continued, and her tail spasmed violently, straining against the netting he hadn't yet cleared away and injuring her further. And then the strangest thing happened. Her tail split open and the gory mess of muscle and bone somehow gave way to two human legs.
Zuko looked back up at her face as the screams abruptly ceased. Whatever had just happened had clearly been too much; she must've passed out from the pain. He pressed his fingers to her neck to check if she had a pulse and noticed that her gills were gone, along with all the other physical traits such as fins which had marked her as a mermaid.
Looking down at the mermaid's unconscious form as he pushed aside the net and gathered her up in his arms, Zuko felt the overwhelming urge to protect her. She looked small and vulnerable, the soft curves of her naked body completely bared to the salty sea air, her long hair a wild tangle of curls plastered over her still damp skin, and her lower newly formed legs dripping with her own blood.
Putting her back into the ocean was no doubt the right thing to do, but not when she was unconscious and in this vulnerable state. Plus he had no idea how this transformation thing worked. Would she be able to control it and turn back in such a weakened state? He didn't want to risk dropping the mermaid back into the ocean only to have her sink beneath the waves and drown.
Zuko hurried over to the closed off section of his little fishing boat where it was slightly warmer and laid her down on the floor. He then hurried back out to fill a bucket with sea water and grab a cloth. He cleaned her up as fast as he could, tossing the cloth aside when he was done. Fortunately, the abrasions on her tail from the netting didn't seem to have transferred over to her legs. Good, he didn't need to worry about first aid right now.
He wrapped a blanket around her and returned to the deck, grimacing as he looked at the grotesque scene laid out before him. No what should he do with the remains of her tail?
Katara awoke with a gasp, sitting upright. Everything felt wrong, her body unused to being immersed in air rather than water. And her strong dependable tail was gone, replaced by the discomfort of human legs.
It had come as a shock when her body shifted, having never gone through the process before, but most of the pain had faded now that it was over.
She was in a small room on a fishing boat, cut off from the ocean by three flimsy walls and a fourth which was partially open to the outside. It was cold in there, and the fabric covering her didn't provide enough heat. Shivering and scared, Katara let out a distressed keening noise which came out as more of a whimper with her human vocal chords, pulling the fabric tighter against herself and curling up to make herself as small as possible. She’d never had legs before or practiced walking with them, so for now she was rendered immobile, unable to escape quickly if she needed to.
Katara heard a noise and looked up to see a human entering the room. He crouched down in front of her and she instinctually backed away, her back hitting the wall. She was fairly certain this had been the human that had cut her free, but it had also been his net which had caught her in the first place.
Half of his face was twisted with scars and his skin looked unnaturally pale, but as far as she could tell he didn't seem to want to hurt her. In fact, he was staying a respectful distance away since she'd flinched back at his approach. She regarded him warily, but he made no move to attack.
"Um, hi," the human said awkwardly, breaking the tense silence. "I'm Zuko."
"... Katara," she replied cautiously, peering from behind her curtain of hair at him.
"You, uh. You look cold," he remarked. "I can warm you up if that's okay."
She looked at him skeptically. Was this human trying to flirt with her? Because now was really not the time.
His hands shot up defensively. "No, not like that! I mean, I'm a firebender, so I can transfer some of my body heat to you.”
Katara scowled. “Why would I trust you? It was your stupid net that caused this in the first place!”
“I… yeah. You’re right. My net caught you. I’m sorry. But I don’t want to hurt you.”
He was incredibly awkward but he seemed to be sincere. “Okay. But if you try anything I’ll attack you.” She hoped that sounded intimidating. She may have been at a disadvantage out the water, but she would still put up a fight if she had to. “And then you’ll be the one who gets hurt. Got it?”
He nodded, taking her seriously. “Yeah. Makes sense.”
Katara nodded and let herself relax a bit. She lifted her hand from beneath the blanket and held it out to him. “I’m cold. Show me your firebending.”