A/N: This was written for a drabble challenge I'm doing on LiveJournal. This prompt was "broody".

~For Savcat, my own personal Sideswipe; always there whether I want her to be or not.~

The Ark was someplace that Sideswipe liked to think of as home. "Home"… a very human term, wasn't it? Because Cybertronians didn't really have one. There was no equivalent in their language for that concept the humans had created. Home was someplace you belonged, simply put. Home was someplace where, if you had to go, they had to take you in.

The Ark was like that. Sure, it got cold and distant sometimes (usually after battles, when the Energon would come out and he watched the others get drunk and laugh and get pointlessly angry) but it was still someplace he felt comfortable when times got rough. And it seemed to him that they were always rough, now.

The war, simply put, was tearing all of them apart. Sideswipe couldn't help but feel parts of himself flake away as he watched soldier after soldier press closer to the idea of death. They'd had a few warriors let themselves die; gave up. A few had changed sides to the Decepticons. Even more had surfaced with a fierce, frightening determination to show the Decepticons what the Autobots were about… a kind of manic craze about them, and a violent dichotomy of black and white.

He could think of countless that fell into that third, unsettling category, but only one that strayed away from all three.

It was silent for the moment and he made to sit still. The sun crept in through the window (his window, damn it, he'd fought for this room and that window was his) and its rays cast the room in a kind of light he wasn't used to yet. Cybertron had always been so dark; Earth was the exact opposite. Earth was bright and loud and crowded. Strange that the Ark should choose here to land, of all planets, of all places.

But it was quiet for now. That was all that mattered to him at the moment, the silence, the blessed serenity that fell between them. He looked up and saw Sunstreaker's hands brush across a canvas he couldn't see properly, saw the look of concentration in those optics. Wanted to break it, terribly, wanted to see Sunstreaker falter and stumble and fail. He'd always wanted to see his brother fail. His twin was so fragging good at everything, and it wasn't fair, not when Sideswipe was so… weak by comparison.

Seen as nice, and funny, and open, all in comparison to Sunstreaker.

"Sunny."

That did it. Sunstreaker paused a moment, fingers stuttering in frustration. He looked down at the canvas and then up at Sideswipe. "What? And don't call me that."

Sideswipe leaned forward so that his elbows rested on his knees. The light caressed Sunstreaker's golden armor and made him look what Spike had called "angelic". Something straight out of Christian Heaven, something forged from life and not from the scrap heaps that was their reality. Not that he'd ever give hint to that. No, not ever.

"I can call you what I want to," he replied with a smile. "Are you done yet?"

"I can't be done when you keep interrupting me. I've startled twice – twice with this picture, and your fidgeting isn't helping. Hold the slag still."

He couldn't. Not a chance. Not when Sunstreaker was here and frustrated and getting worked up, all over a mistake. There was something wrong with this. Normally… well, Sunstreaker was a perfectionist, yes, but he was usually calmer than this. Something had happened, or someone had said something, and Sideswipe had to be a good twin and pry.

"You're the one who's fidgeting, Sunny. Look at you. You're shaking."

Sunstreaker fell quiet. "I don't shake."

Sideswipe watched him look down at his hands. Fingertips tipped with different colors of paint, graceful and wet, attractive like the rest of him. Also trembling, only the slightest of tremors that had him so jumpy, so nervous, yellow optics constantly darting toward the doorway as though expecting Primus himself to wedge himself inside.

"What's wrong?" No reply, and Sunstreaker took up his paints again, looked back to his flawed and tragic canvas. Frustration welled in Sideswipe and he stood, came over, and gently slid the easel aside to face his brother. "Sunstreaker. What's wrong?"

Quiet. Oh, so quiet, quiet enough to hear the gentle hum of a working motor, the purr of rotators turning in their sockets. Every sound a treasure, every moment something to commit to memory. It wasn't always like this, though. There were times when all he wanted to do was take his twin and throw him through time until he came out the other side a deadened wreck. Perhaps that's why he so looked forward to these kinds of moments, quiet ones, loving ones, the ones when Sunstreaker would maybe… just maybe… talk to him.

Even a little bit.

But Sunstreaker didn't. Instead, like he always did, he turned away and put his brush back into the little cup of water, optics narrow and blazing like the Earth's hot, small sun. Passion. Anger. It was hard to like, but so incredibly easy to love.

"I hate it when you do this, you know," Sideswipe cut into the silence, and couldn't help but let the anger scorch his tone.

Sunstreaker continued placing his supplies back where they belong. "When I do what?"

Of all the nerve…

"When you avoid me. When you… shut up like this, push people out. I only want to help you, Sunny, it's all I've ever wanted." He noted the way Sunstreaker's shoulders sagged, the drag in his step. The pure depression that lined his frame. It wasn't like him. Suddenly he longed for Sunstreaker to hit him, to yell at him, to do something other than just… close up.

"Tell me what's wrong."

"Nothing's wrong."

"You say that every time I ask. Something is wrong, or you'd be bitching to me like you usually do." Still no response. He took a step forward, reaching for his twin's face, and Sunstreaker hit his arm away.

"Don't touch me!" he shouted, and Sideswipe heard bitterness and sadness and something unidentifiable in that voice. "Primus, why are you so insistent?! Just leave me alone to do my painting or to brood or… whatever. Go bother someone else."

Maybe not as serene as he would've liked to think. But this was good too. He didn't mind when Sunstreaker yelled, or complained; it was the shutting down that he minded. It started this way, and had happened too many times to accurately count (though Prowl could've told him, to the decimal). Sunstreaker would brood. Close up and not talk and seethe silently to himself about something, whether it be colossal or nondescript, and Sideswipe would ache to help, just like he was aching now.

Sunstreaker would get violent and lash out and some poor unsuspecting Autobot, usually Bluestreak, Red Alert, Huffer, or Brawn. He'd be sent to the brig and Sideswipe would visit and still, Sunstreaker wouldn't talk.

His twin would fume himself into a repressive storm until he fried some vital circuit from the stress alone, and wound up in the med bay. Sideswipe would pretend to have no sympathy, but in reality, would yearn to make it better just like he always did. He hated seeing Sunny hurt, more than anything.

He wouldn't let that happen now.

"Sunny, please tell me what happened."

"Uh-oh, you used the 'p' word. You must be worried," Sunstreaker ground out with dripping sarcasm. Sideswipe wanted to hit him. Nearly did, but managed to refrain.

"I am!" His voice rose a bit higher than he would've liked, and he forced it back down to normal. "I am. Something happened. You're upset. I have to be the Good Twin and make it all better."

That earned him a sharp, bitter laugh. "You can't make anything better. If anything, you have the unnatural ability to make it all worse. Especially in my case!" Sunstreaker waved a hand. "You'll get frustrated with me, and we'll argue about it, and maybe we'll get up the energy to interface, and eventually you'll leave me with this black, sucking hole inside of me and really, it's a wonder I haven't gone Decepticon already, because you drive me crazy."

Sideswipe looked at him a long moment. Intensity flared between them and he couldn't help but feel that Sunstreaker was right. Whatever they had, it certainly wasn't helping either of them. Though Sideswipe knew that Sunstreaker had lost his sanity long ago, at the forge of their bond, at the feel of that connection tying him down. Tying them both down. Keeping them trapped in one another's arms.

"I just wish you'd let me try. Just… tell me what happened to you. Even if it'll only make it worse."

Sunstreaker looked pained. Pained and indecisive and torn between two decisions. "Blue—" But he cut himself off again, shook his head. "No. I won't do this. Not to him, not to you."

Bluestreak. So that was the problem. Envy and a burning, unnatural anger flared deep within him, and he had difficulty fighting it back. Everyone wanted a piece of his twin. Everyone wanted to screw Sunny up so bad, wanted to mess with him and hurt him when all Sideswipe wanted was for him to be here, was for him to stay.

He couldn't have his twin in pieces. Not again. And not over someone as stupid and happy-go-lucky as the sniper.

"Aren't I enough for you?" he asked, lowly and with extra hurt. He knew where Sunstreaker's buttons were. Knew how to get his twin to break down, knew where it hurt, knew that his brother was a sucker for misery. "Bluestreak can't give you what I can give you. I… just thought I was enough."

Silence again. Then, tensely: "You'll never be enough to satisfy me, Sides."

Fresh anger. He'd forgotten; Sunstreaker knew where Sideswipe hurt as well. And it was working. He couldn't stand the thought of Sunny giving himself over to anyone else again, only to have it end in pieces. Couldn't stand the thought of other mechs touching him, couldn't stand Sunstreaker falling for anyone but him.

"Why not?" Rage made his words low and threatening. He took another step forward and his twin matched it. Their equal heights allowed Sunstreaker to glare deep into his optics, allowed them to face one another with all of the pain, all of the hatred and all of the hurt they were feeling.

"Because you're not good enough for me."

And the words hurt him like a blow, and he knew they were meant to. Sunstreaker was provoking him, for some unknown reason, and Sideswipe was eating up the bait like a treat.

He wasn't even entirely sure of what had happened. Just that, suddenly, Sunstreaker was against the wall, and Sideswipe could feel the frantic pulsing of rage and denial and anger and greed coursing through him. Envy, unexplainable jealousy. Sideswipe scrabbled metaphorically for something that would show his twin that he was just as good as the next mech, just as strong, just as violent…

Took Sunstreaker's shoulders and crushed them hard to the wall until he heard the armor bend and crack. Sunstreaker choked on some kind of human curse and looked him directly in the optics as though daring him. Stupid; they both knew how far Sideswipe would go. And he took Sunny's chin in his hand and wrenched it up, pulled it sharply forward into a crushing kiss, sensors blaring with the need to dominate.

"Mmn—" A noise of static and pain. Good. Sideswipe brought his twin closer, violent and needing and his hands were crushing but Sunstreaker's were suddenly everywhere.

Warmed, heated metal pressed to his own and he pressed himself closer, close as possible without hurting him further. Sunstreaker didn't mind, complied far too obediently, enthusiastically, arms wrapped around him in a firm embrace that allowed for nothing else.

Like I need anything else but you. Prowl would be nice, yes, but you're the one who stays. You're the one who touches me and lets me feel, you're the one who shows me that I can be hurtful too. Though I'd never hurt you, Sunstreaker, not the way you want me to. I could never hurt you that way.

I love you, you slagging idiot. Why do you have to rub it in my face all the time?

Good. So good, the feel of his own fingers working Sunstreaker's small, hidden compartment open, and his twin was shuddering in anticipation, trying to work on his own but there was no space to do it. Sideswipe wouldn't pull back from the kiss, not now, not ever, fingertips scraping along Sunstreaker's perfect paint until it left silver scratches into it.

"M—cck—Mmmn!" Sunstreaker struggled now as though in pain, and Sideswipe loved it, watching him writhe when he'd barely even traced the casing. It was something sick and twisted and wrong, just like they should be. Cybertronian twins shouldn't exist, not like this. They were wrong, and this was wrong, and they would take it all with them. Sideswipe would make sure of it.

He pulled back from the kiss to hear Sunstreaker try and stifle his cries, to watch him try and shove him away. "Sto—Ah, stop…! Stop it!"

I can't. You do this to me and I'm giving you what you want. Selfish glitch.

Sunstreaker's optics were flickering with what looked like pain, and soon he'd worked open his own compartment as well, and it left both of their sparks bare, vulnerable. He knew how much his twin hated this, knew how the other favored holograms over anything this real. Hated facing reality dead-on, and Sideswipe loved the look of uncertainty mingled with the expression of panic.

"Don't—"

Pulsing. Blue and bright and shivering under that beautiful armor, and how could he resist? It took only a moment to press them close, press them together, to feel that flowing and sweet electrifying energy shudder between them. Felt far too good and hurt far too much for either of them to stop. Sunstreaker gripped him and his legs came up to hook around his waist, and Sideswipe had him safe and sturdy against the cold wall, and they both arched and shivered and their optics were blazing with the horrific passion of it all.

"Side—Side—Primus…!" Sunstreaker tried to muffle himself against Sideswipe's armor. The whirr of gears and buzz of electric sparks was nearly too loud in his receptors, and his twin just looked so beautiful as he tipped his head back, groaning a loud and mechanical noise, mouth opening in a final and silent cry before he overloaded.

Sideswipe followed with all the violence he'd put into making this happen. It was sweet but it hurt as well, shaking deep inside of him like those hands were against his armor. It was over as quickly as it had begun; Sunstreaker was whimpering soft and pitiful noises against him, and Sideswipe held on for all he was worth, because Bluestreak could never do this for him, could never be that violence that Sunny needed, could never…

Could never take his place.

Bluestreak could never be Sunstreaker's other half.

They sunk to the floor and held one another and their sparks glowed within them with a deep, deep unhappiness that could never be mended. Not by Bluestreak, not by Prowl, and certainly not by one another.

Because when all else failed, this was still there. This rage and violence and hurt. This was there to bring them close, to bring them back to reality when they became distracted by wants. This was there to take him in when he needed someplace to go.

"I love you, Sunstreaker."

The lack of a response didn't bother him. Instead he just held his twin and would've cried if that were possible at all for his kind, and thought about how good, how wrong, how scary it felt to be home.