Disclaimer: I don't own transformers.
I was browsing the TF Bunny Farm and I found this. It would not leave me alone; so I gave it a shot.
The plot bunny was this: [G1] AU. At the beginning of the war, Sunstreaker joined the Decepticons as an Autobot spy under the name Spinout. No one knows that Sideswipe is "Spinout"'s twin. a. For that matter, not even Jazz knew. b. Or Prime.
Sentinel Prime was getting worried. This rebellion had been uncurbed for too long, and they had taken several of the higher class cities.
Tarn was destroyed, Kalis was destroyed, Praxus was a battleground, Vos had sided with the rebels after an unfortunate incident involving a 'up top' decision that the seekers were too dangerous. They had pretty much sided against the autobots at the time of the missile strike anyway.
They needed an edge. Someone he could trust to infiltrate the decepticons and not betray him . . . someone who actually was that violent on the battlefield . . . hmmm.
"REBOUND! FIND ME SOMEONE WITH THESE SPECS!" He chucked a datapad at his assistant. "And do it swiftly, this is a matter of great importance." The resigned mech caught the datapad and walked off to do his liege' bidding. Sentinel owned him, ever since he had bet his own frame in a game. Primus, that had been a bad idea, but he was overcharged. Still, waking up being told that you belonged to someone was not a good experience. Sentinel could sell him as a pleasurebot, could offline him, store his spark in Vector Sigma and reuse his frame, whatever he wanted. Rebound wasn't his own mech anymore. And yes, it was scrap.
Rebound checked the datapad out and groaned. He could just grab a random mech and take him to Sentinel. Much easier. Five orns later, Sentinel was sitting his cushy office facing a yellow mech who looked far too shiny to be a grunt. Still, as long as it wasn't illegal. Last he checked, it wasn't.
"So, you are?" He inquired. "Sunstreaker" the yellow mech growled at him. He frowned at the lack of respect. "Let me make one thing clear, Sidestreaker-
"Sunstreaker"
"Whatever. I am Prime. That title deserves respect and I demand you show it to me. Understood?"
"The title does deserve respect. You don't. I believe in autobot ideals, not the mech prancing about demanding respect from everyone who nearly dies for his faction every day."
The Prime glowered at him. He forced himself to calm, maybe this was for the best. He was sending this mech off away from his friends, isolating him with brutal decepticons - maybe it would teach him to respect his elders. "Look here, I need an edge in quelling this rebellion and I decided that you are best suited for the task of infiltrating the decepticons. You will, in all respects, be a decepticon until I have enough information. Your new designation is Spin-out, and you will be repainte-"
"No. I'm a frontliner not a spy. I am not taking on that designation and the cycle one of your goons touches my paint job will be his last. Besides, my twin is here. I will not leave him."
Sentinel narrowed his optics at the mech, seeing him in a new light. It would be much better for the autobots as a whole to have this primus-cursed disrespectful freak away in the decepticons. Twins were abominations, defying Primus' will and splitting. They were bad luck, accursed, damned to the pit. This mech was going. No question about it.
Sunstreaker was glowering at him now. Keep calm, keep calm. I must get him to accept the mission! "Sunstreaker. I have experience with twins, and I assure you, nothing bad will come of you and him being separated. I am not asking you to do this for me. I am asking you to do this for the autobots, for your twin. We need to win this war, and to do that we need you to pass us information from the 'cons. I assume you can handle it?"
The twin stared suspiciously at his outstretched hand and asked cautiously, "You will assign someone to watch over Sidewipe? Make sure he's alright?" A note of vulnerability entered his tone and in his mind, Sentinel grinned like a shark. Bingo.
He put on his best Primely face, and replied "I will do all I can." Sunstreaker looked indecisive. Eventually, it was inevitable that he accepted the mission. He had two choices. Do the mission right or defect to the decepticons on the mission. The second one was never going to happen so it had to be the first. "Fine. I leave in two orns." Sentinel actually did grin then, a smug look on his faceplates. "I knew you would agree." Sunstreaker scowled and stalked out of the prime's office, privately thinking to himself; What the frag have I just agreed to?
Three orns later, the decepticons had a new recruit. Spin-out, a young mech with good fighting skills, violent impulses and sociopathic tendencies. He had a red visor to hide his blue optics. His frame was upgraded with more dangerous weaponry and high-tech communications, as well as spikier and more dangerous looking armour, but he still hadn't let them repaint him.
Sideswipe stayed in his current frame for the next million years or so, waiting for Sunny to come back from his mission with enough information to allow him access back into the autobots.
Sentinel had left no loose ends. He wanted the information with the autobots, and those Primus-forsaken twins offlined. Sunstreaker was labeled as a traitor, and Sideswipe was sent off the the most remote or dangerous bases possible, until a new prime emerged.
Sideswipe returned to Iacon, and was eventually accepted into the prime's unit. However, Spin-Out was still with the decepticons. Sideswipe was sure he'd return eventually though. He could feel it in his spark.