A/N: The title for this fic comes from the song "Sad Machine" by Porter Robinson. As much as I want to, I just can't stop associating it with Aang and Katara.

It's my personal headcanon that, even though Katara struggles with her feelings for Aang over season three, the moment she started considering him as something more than a friend/little brother was while he was unconscious after almost dying. So that's what this fic is going to explore (among other things).

Also, sorry this chapter is short. The others are longer.

(Apparently, there's a comic for this concept, which I didn't know about when I wrote this. So, if something doesn't line up, that's why.)

She woke to a Fire Nation emblem emblazoned on a tapestry above the bed. The sheets were red, the walls were steel, and the creaking of the warship around her was never something she associated with the wooden boats of the Water Tribe. Katara stumbled to her feet, nearly falling over in her haste to unwind from the blanket. By the time she reached her waterskin, left laying on the floor next to her, Katara was awake enough to remember herself.

Moving slower, she set the waterskin back down and looked around her. Sokka and Toph were passed out on the floor, next to where Katara had been sleeping. The ship had plenty of rooms for all of them, but after what happened, none of them wanted to be separated again. The only reason they weren't sleeping on the floor in Aang's room was because—

Katara felt a pang in her chest and her breath caught. Right. Because Aang was dead. Or unconscious. Or something in-between. Whatever he was, he wasn't waking up, and Katara had been too tired to argue when her dad ushered her to a different room from Aang's and told her to get some sleep.

Hakoda probably just hadn't wanted his kids to wake up to a dead body in that bed. Aang's fluttering heartbeat was so weak and his injuries were so severe that it wasn't an unfounded worry.

She forced away the memories of her nightmare still clinging to her thoughts. Katara was being ridiculous, and she knew it. Aang was fine. Well, maybe not "fine," but his heart was beating. He had opened his eyes and smiled at her before succumbing to unconsciousness again. That had to mean something. Right?

Glancing down at Sokka and Toph, curled against each other in a way they would both vehemently deny once awake, Katara knew she should rejoin them. She should go back to sleep and do her best to recuperate. It had been a day since the fight against Zuko and Azula in the catacombs beneath Ba Sing Se and her muscles still ached from it.

(But then she closed her eyes and could taste the electricity in the air, could see Aang plummeting, could feel his limp body in her arms, distinctly couldn't feel his heart hammering or his lungs drawing breaths.)

Shaking her head, Katara left the room. The halls of the Fire Nation warship were more unfamiliar in the pitch-blackness of the night than they had been in the daytime. They had left lanterns on at each end of the halls, though. Katara followed them forward, picking her way carefully up to the deck of the ship. Thankfully, she wasn't very deep beneath the deck.

Surrounded by Fire Nation steel, like a prison, Katara hadn't been able to breathe.

On deck, she was greeted by a waning moon and the gentle lapping of the ocean against the sides of the boat. She remembered sinking the ship after Toph punched a hole in it, making it fill with water while the Fire Nation crew abandoned their ship. Then Katara had raised it again and Toph had smoothed out the enormous hole in the ship's hull and it was like nothing had happened. Except for that precious hour she'd been forced to spend away from Aang's bedside, wracked with guilt and terrified that she would return to find him dead again.

(She kept wishing that she had dragged the ship's crew down, too. It was the least they deserved, she thought, after what they did to Aang's people, to her tribe (her mother), to the entire world. But then the of some of those soldiers, boys and girls barely older than Sokka, would resurface in her mind's eye and Katara was glad she hadn't done it. She couldn't keep from considering it again every time they passed another Fire Nation ship. But she didn't. And that was the difference: she didn't.)

Flickering torchlight washed over it and the heat reminded Katara, faintly, that she was cold. She hadn't grabbed a robe before going up on deck and she was still dressed in her torn and burnt Water Tribe dress. She turned and stiffened at the sight of a Fire Nation Army uniform, only to relax when Bato's face registered a second after. "Katara?" He asked, surprised. "What are you doing awake this time of night? You should cover yourself when you're on deck, even if it is dark."

Katara forced a smile that probably came out as more of a grimace. "I forgot," she said, which was honest enough. "I just… wanted some fresh air. Sorry."

Bato's expression softened with pity, a look that Katara hated. He had been able to see through her for as long as she could remember: since she would go outside for "fresh air" every night for months after her mom's death. Anything to avoid sleeping and returning to the nightmares.

He looked at Katara like she was six-years-old and tiny and helpless and scared all over again and she hated that more than anything. She hated that all of those things were true, a tangled knot in her chest that made her want to hug Bato and cry into his shoulder.

"Do you want me to get your father?" He asked, gently, and the urge to hug him passed.

Katara drew herself up straighter, smoothing her expression over as best she could. "No," she said airily. "I'm fine. I think I'm going to go back to bed."

His frown tightened. "Katara—" Bato tried, tone pleading.

"Goodnight, Bato!" Katara waved cheerily as she stepped around him and headed back the way she had come. Bato didn't call after her again and he didn't try to follow her. The most infuriating part was that Katara didn't know if she wanted him to or not.

She stepped back inside the interior of the ship and paused. Instead of going left, back to her room where Sokka and Toph and a nest of blankets were waiting for her, Katara went right. She knew exactly where she was going, who she needed to see.

It would have been easy to get lost on the huge warship, but Katara didn't doubt the turns she made and she came to the room she wanted quicker than she could have gotten back to her own. They had picked it for Aang because it was the first one they had come across that wasn't waterlogged and the desire to get him somewhere to rest so she could spend more time healing him had been all that mattered to Katara.

The door wasn't locked. Of course it wasn't — that first required the occupant of the room to be awake. Katara eased it open, careful to be quiet. There were two lanterns glowing dimly at one end of the room, opposite the bed. Despite the low light, it wasn't hard to see. Katara almost wished that it was darker as she drew closer to Aang's bedside. A part of her wilted, seeing him like that.

Other than the lightning burn that dominated most of his back, breaking up the proudly-earned airbending master tattoo that traced its way down his spine, Aang had plenty of other injuries. They were less severe, sure, but Katara didn't think that made the burns any better. The one on his bicep was probably going to leave a faint scar. His shoulder had been bleeding when they got on the ship, a blister that had split open, so it had been padded with gauze and wrapped along with his forearm. There were still more bandages sticking out from beneath Aang's torn and singed pants, wrapped around his knee and shin.

It wasn't right. All Aang had ever tried to do was help people — what would he have done to deserve this?

Katara swallowed a sigh. She pulled a chair up to Aang's bedside, content to just watch him for a moment. With her gaze trained on his chest, Katara could watch it rise and fall with his breathing. Corpses didn't breathe. He was alive, she kept telling herself, and that was a start. Staring at Aang's chest made it impossible to ignore his bandages, though.

She had to close her eyes, remembering Sokka frantically digging through medical supplies as Katara steered Appa toward Cameleon Bay to meet up with her father's fleet. Sokka had been the one to pry Aang from her arms, though Katara certainly hadn't made it easy on him. A part of her had been convinced (was still convinced) that to let Aang out of her sight meant his heart would finally stop stuttering and give out.

But Sokka had been as calm as she'd ever seen him, wrapping the wounds, directing Katara to heal the more minor injuries before wrapping those too. And when they had landed, at his direction, Sokka had left her and Toph to look after Aang while he explained the situation to their dad.

Sokka had given her that moment to be weak. Briefly, Katara wondered what he would say if he could see her now. She had been the strong one after their mom died, the one who pulled their family back together, though the loss had left her feeling like her chest had been split open and she would never be whole again. But looking at Aang, Katara could only think that she was so tired of being strong. (She liked to think that Sokka wouldn't have judged her, that he would have hugged her and sat with her because he was just as torn up as she was.)

Because Aang had died. Katara had felt it not seconds after she stopped his plummet, catching Aang in her arms. She had felt his last breath and that his body was going cold even as the bloody burn on his back pulsed hotter than ever. He had died in her arms, but there he was anyway, still breathing.

For all intents and purposes, Katara knew that she had failed. If it hadn't been for the Spirit Water from the North Pole, Aang would have died. And it would have been her fault.

(Images from her nightmare drifted back to her then. Katara hadn't woken up screaming, but it had been close. In her dreams, Aang had died and he had stayed dead. Katara had been sobbing over his body, trying again and again to force his corpse to take the Spirit Water, but she never succeeded. The image of his body spasming, lightning cracking in the air, blood boiling as it oozed out of the splits in his skin, all of it was seared into her mind. Katara knew it would never go away, that it would haunt her for decades to come, and she didn't think that she deserved to be free from the mental torment, regardless.)

Katara moved her chair closer to Aang's bedside, glancing briefly at his face. He looked uncomfortable. At some point between moving him from Appa's back to the bedroom of a Fire Nation warship, Aang had lost his peaceful expression. She took hold of his hand and wondered if he was running hot or if Katara was running cold.

Her fingers curled around his wrist, slim and limp in her hand. Katara closed her eyes. His pulse was weak, but it was there, fluttering and fragile. Every pause between beats made her chest tighten and her throat close, her worry consuming her, but then Aang's heartbeat would continue as though that second where it hadn't been pounding was nothing but Katara's overactive imagination.

And maybe it was. Katara felt frayed, at her wit's end, and she had only been on the ship for a day. She felt like crying. Even when she was awake, her nightmares refused to go away.

Stubbornly, Katara blinked away the stinging in her eyes. There was a bowl of water at Aang's bedside and she drew a thin stream from it. Carefully, she molded the water into smaller balls and eased Aang's mouth open with her other hand. It was important that he stayed hydrated, although getting him to eat was no doubt going to be more difficult. Katara got him to drink the water without incident, but when she settled back down again, she found her anxious hands making a mess of her braid and her leg bouncing impatiently.

It took another minute of agonizing anticipation before Katara gave in. Slowly, she rolled Aang over into his back. He twitched and jerked, groaning in displeasure, but his eyes only seemed to squeeze themselves shut even tighter. Katara bit her lip against the guilt and began carefully undoing his bandages. A little midnight healing session had never hurt anyone.

(And if the healing session was more for Katara's benefit than his, well, she got the feeling that Aang wouldn't have complained.)