Mild character spoilers for Revenge of the Fallen.

o o o

They had been the best. A perfectly balanced duo of massive destruction; sleek, beautiful, deadly. They had been among the Autobot's top frontline warriors.

They had also been twins.

Doubled sparks like their own had always been a mystery, even to twins themselves, for millennia. But research into such a delicate topic, with it's high potential for violating the personal freedoms and thoughts of the 'subjects', was frowned upon in Cybertron's society. Then had come the war, and the Decepticon's dismissal of such concepts as personal freedoms, and they had been caught. Their queer double-spark had been examined, prodded, tested. Their minds had been tested in much the same manner, looking for the fabled 'Twin-bond' that, in his experience, was just two parts familiarity with each other and about five parts urban legend. And when no bond had been found, the researchers had tried forcing a telepathic bond between them, with painful and futile results.

By the time the Femmes had been brought to the research facility, Sideswipe barely even cared. Everyone knew who the Femmes were; the delicate alien warriors who swore themselves to the Autobot cause. Their species had a form of mental bonding that intrigued the Researchers, and though it must have cost the Decepticons dearly to capture all three alive and whole, they quickly made up for the loss in knowledge gained from the Femmes unique structures, so like and so different from Cybertronian. By the time the first few rounds of their experiments were done, the Femmes had been wrapped around each other's minds until it was near-impossible to distinguish one from the other on the basis of personality alone.

When Jolt came in, Sideswipe was ifar/i beyond caring. The little warrior had been the first in a new line of research, an attempt at splitting a spark to make a twin set from one mech. All the attempt had done was split Jolt's mind instead, leaving him outwardly unstable and probably insane.

When the Researchers got their claws into a second set of True twins, Sideswipe almost didn't care - until he saw them. They were children, recently sparked and so young, so very young, but they fought the researchers at every turn with a very adult grit and determination and a vocabulary that made Sideswipe smile grimly. They weren't even old enough to be considered warriors yet, and here they were, fighting for each other with everything they had. And soon enough, they'd be broken, just like Jolt. Just like the Femmes.

Just like Sideswipe and his brother.

Sideswipe and Sunstreaker shared a long, cold look. Enough was enough.

o o o

They ran, past empty planets and cold stars and long, painful stretches of space. They ran and Sideswipe's spark hurt with every passing klik, because Sunstreaker wasn't with them. The gold twin had held back, had covered their escape, and for the first time, Sideswipe regretted the lack of a twin-bond, because at least then he'd know if Sunstreaker was alive or dead.

And he couldn't go back and look for Sunstreaker, not now. Because now he was a leader, because he had a responsibility to the mechs he was with. Jolt was too unbalanced. Chromia-Arcee-Moonracer was too caught up in her own trebled mind to be more than vaguely concerned about anything else. Mudflap and Skids just didn't know enough to make it on their own. If Sideswipe abandoned them to search for Sunstreaker, they'd all fall prey to the Decepticons within breems. And if he found Sunstreaker, after all they risked to break the others out of the facility only to abandon them, his twin was likely to remove his head for him.

So, they ran. And Sideswipe used every trick in the datapad to keep them together. He cajoled, he threatened, he pleaded, he used blunt force when no other option was available. And, somehow, he got them to act as a team. He got them to work, somehow. He got the Femmes out of their dreamy cloud-mind. He coaxed Jolt back into something like normality. He taught Skids and Mudflap the facts of life that they should have learned from their creators and the youth guardians. And, somewhere in there, he figured out how to be a mech that wasn't defined as Sideswipe, killer of Decepticons, or Sideswipe, twin of Sunstreaker.

Then they found the Prime's missive, and followed it to earth. And when Optimus sent out his second message, from the flight deck of the Stennis, Sideswipe added his own to it's tail. No secretly hidden, carefully coded 'I-hope-he-finds-this' note left carved into the rocks of a dozen dead planets; this was a brazen invitation riding on the strength of the Prime's transmission. A call to his brother, 'I am here, come back to me'. A call to the Researchers, 'You want us, come and get us'. The Prime did not approve. His team did.

Time passed, the war continued. And Sideswipe waited.