Notes: CRACK. TOTAL CRACK. :D Mild, non-explicit smut.

4. kindred spirits

Sunny, get down here. You've gotta see what I've got in my shop right now!

Sunstreaker sends a sharp negative through the comm, but his brother is insistent.

No, seriously, you're not gonna want to miss this.

Long practice – more instinct than thought – picks out the enthusiasm, the barely contained excitement in Sideswipe's tone. Whatever it is, it isn't a trick, or a bored ploy for attention; the question just remains as to whether whatever it is that's got him worked up this time is going to be of any actual interest to Sunstreaker. Twins or not, shared spark or not, their tastes are far from identical.

But he supposes he's not that busy, and some of Sideswipe's finds really are something, sohe sets aside his polishing cloth and heads on down to the shop floor.

The first thing he hears when he gets there is Sideswipe explaining the finer points of some sort of trigger mechanism in the particular tone of voice that Sunstreaker knows, intimately, means he's plotting something that will probably get them into trouble. The only thing is, Sideswipe never uses that voice except with him, and Sunstreaker is scowling when he shoves open the door and steps inside.

The scowl freeze-fades when he sees who Sideswipe's talking to. A Seeker – an honest-to-Primus Seeker – leaning against Sideswipe's workbench and listening with rapt fascination – all graceful wings and slender limbs and effortless, arrogant poise, and Sunstreaker understands then why his brother has called him down here. It's all he can do not to walk right over there and run his hands over that curving cockpit, slide his fingers around a tempting aileron, press his mouth to the sleek grey metal of throat and face. He reins in the impulse with a shudder, still unable to tear his gaze from the beautiful jet – oh, he's dreamed of getting this close to one of them for vorns – and that's when the details of what Sideswipe's saying finally penetrate.

He does look away then, focusing on his brother with sharp concern.

"Sides," he snaps, "what the Pit do you think you're doing? You have any idea how much trouble you could get us in?"

The Seeker cranes his head to look at him, surprised by his presence but not alarmed, while Sideswipe just laughs dismissively.

"Shut up, Sunny, this guy's come up with the best idea ever."

"He's gonna get fragged and you're gonna end up on the scrap heap with him if you're planning what I think you are!"

From the left comes an exasperated sigh.

"That's what I keep telling them."

Sunstreaker snaps his head around, startled – he was so fixated on the Seeker that he didn't even realise someone else was here – but whatever he might have said dies on his vocaliser as he realises that this speaker, too, is a jet, built on exactly the same lines as the one now discussing Primus-knows-what havoc with his brother. Just as enticing, just as breathtaking, just as gorgeous as his companion – but more than that, Sunstreaker's attention is drawn to the expression on his face.

It is a deeply familiar expression. It is the expression Sunstreaker often finds himself wearing when dealing with Sideswipe's latest scheme: irritation, mixed with reluctant affection, mixed with the knowledge that it's going to be him that has to get them out of this.

The Seeker meets his optics with a more than a touch of defiance, as if he's expecting Sunstreaker to start demanding explanations, maybe threaten to call the authorities and report them; but that moment of unexpected kinship has defused his initial anger, and besides, Sunstreaker is well aware that whatever they're plotting, Sideswipe is already up to his neck in it. He casts a resigned glance at the two by the workbench – oh, Primus, Sides has got the turbo fuel cells out, this cannot end well – and approaches the other Seeker.

"How long?"

"What?"

"How long've they been at it?"

"Almost a two joors."

"And they're still going? Slag."

Sunstreaker sees it happen – the Seeker reads in him what he's already seen in the other, and the faint threat of hostility vanishes from his face as he sags against the wall with a groan.

"Yeah. I should never have let him talk me into this."

"Tell me about it."

The Seeker hesitates, then offers a hand. "I'm Thundercracker."

"Sunstreaker." Sunstreaker grasps his arm, then jerks his head towards the pair on the other side of the room. "Guess you've met Sideswipe. Who's your friend?"

"Skywarp." Thundercracker casts a dire look at the Seeker in question, who is tossing a highly volatile fuel cell carelessly from one hand to the other. "We just came in to get a couple of parts. Next thing I know, they're halfway to breaking fifteen different laws, and that's before they started arguing about the best way to test it." He shakes his head. "I shoulda knocked him out and hauled his aft out of here at the start."

Sunstreaker snickers. Thundercracker shoots him a quick grin; it looks good on him, lightening a face that's otherwise a little drawn in on itself in a perpetual half-frown. His gaze lingers on Sunstreaker perhaps a few astroseconds longer than is strictly polite, and Sunstreaker makes sure that when he leans up against the wall he arranges himself to show off his best features.

They stand side by side and watch as Sideswipe snatches the fuel cell out of mid-air in the middle of one of Skywarp's tosses, turning it over so he can prod at its inner workings haphazardly with a screwdriver.

"How about we hit them both at the same time, then drag them in opposite directions and make sure they never meet again?"

It's Thundercracker's turn to laugh, the sound low and shot through with harmonics that stir Sunstreaker's spark even more than the sight of him does.

"Skywarp can teleport."

"Ah."

Another pause. Sunstreaker eyes his brother, thinks Sideswipe's going to be entirely preoccupied with his new friend for a while yet, and decides that this is far, far too perfect an opportunity to be wasted.

"I just got a batch of high-grade in a few orns ago. Wanna get so overcharged we won't notice when they bring the place down around our servos?"

"Frag, yes," says Thundercracker, grinning again, and Sunstreaker doesn't even bother to tell Sideswipe they're going – it's not like he's paying attention – as he leads the Seeker out of the workshop.

In the end they barely get as far as their second cube of high-grade, because that's about the point that Sunstreaker can't stand just to look any longer and reaches out to touch, and Thundercracker grabs his arm, but not to stop him – he guides Sunstreaker's hand to his wing, shivers under the touch, clutches at Sunstreaker's waist with eager fingers.

Sunstreaker is used to being an object of desire, used to awe and pleading optics and whispered words of devotion, but he is the one worshipping this time, paying scant attention to his own needs as he runs his fingers over every curve, every dip, across smooth, supple plating and sensors calibrated for the quicksilver reactions of flight. He has been invited to touch and he is not going to waste the opportunity, mapping out the places that get Thundercracker to moan, or gasp, or cry out, in that glorious voice that makes Sunstreaker shudder with need.

Afterwards, it takes a while for Sunstreaker to start thinking clearly, to pull his processor away from the delicious heat radiating from the jet, from the way he hasn't pulled his fingers out of Sunstreaker's wiring, so that every idle twitch sends a little shiver of pleasure to his spark, from the satisfaction of sensing of Thundercracker's utter, luxurious relaxation, limbs so entwined with his that he can hardly tell where each of them begins and ends.

With the return of coherency comes a hint of unease; he'd have killed his twin if they'd been interrupted, but he's surprised it hasn't happened. Either Sideswipe and Skywarp are still talking – which doesn't bode well – or they've gone off somewhere to put their plans into practice – which bodes even worse.

As if reading his mind, Thundercracker murmurs against his helmet, "Should we go check on them?"

He makes no move to disentangle himself, and when Sunstreaker idly begins to run his fingers up and down one of the vents on his shoulder, Thundercracker laughs, low and pleased, and moves his mouth to bite gently one of Sunstreaker's helmet fins.

Sunstreaker activates his comm.

Sides? You still in one piece down there?

Hey, Sunny, where'd you go? You're missing all the fun! Skywarp can do the most amazing things with a wrench and a coil of rubber tubing--

I don't wanna know.

Sideswipe snickers, his tone edging into teasing.

And how are you and Thundercracker getting along?

Thundercracker seems to realise Sunstreaker is talking to his brother, because he hasn't interrupted, but he also seems determined to win back his attention. Sunstreaker stifles a gasp and tries to keep his voice steady.

I'm thinking of trading you in for him.

Sideswipe laughs over the radio link.

That good, huh? Don't ever say I never do anything for you, bro.

He cuts the link before Sunstreaker can come up with a suitable retort – which may be just as well, because Thundercracker has started his turbines spinning, slow and subtle, and the vibrations are making it unlikely Sunstreaker could put coherent words together anyway.

Just as his cooling fans kick in – just as Thundercracker groans and presses closer – just as Sunstreaker is reaching for those beautiful wings again – the building shakes with the muffled roar of what is unmistakeably an explosion. They freeze, staring into each other's optics with a mixture of alarm and shared resignation. A moment later, they hear a pair of voices whooping with unholy glee, swiftly getting closer.

"Primus below," mutters Thundercracker, "we've created a monster."