Standard disclaimers apply, as per usual. Crossover's exact identification comes at the end of the story.

And Impulse isn’t listening. Which, in itself, is nothing new.

The fact that he isn’t listening because he's too busy concentrating on something else (which isn't a videogame or a TV screen), however, is just a little weirder.

‘So. You’re saying the Boom-tube… thingy up and dumped this chick in the speed force… and Impulse pulled her out again?’

‘Before she could be compounded into pure energy, yes.’ Robin barely looks up from the console in order to cast his gaze at Kon. ‘Basically, that’s what happened. They had some difficulty due to compatibility – turned out she wasn’t quite as fast as the speed force wanted her to be, hence the rather large tear-marks going right through Metropolis right now –and by the way you’re talking to Superman about that. But that’s definitely where she came from. Getting her back is going to be the hard thing. I'm fairly sure she ended up there by accident probably as the result of some kind of power shock.’

Superboy opens his mouth to protest –because, heck, he has nothing to do with the skid marks going right through Metropolis and no way is he taking the rap for this – but the actual protest never emerges. He’s too busy looking at the newcomer. And, meanwhile, Bart…

Well, Bart is still looking at the newcomer too, who, as it happens, is staring right back at him with her arms folded and a freaked out, vaguely familiar look on her face. The only thing she doesn't seem too confused about is the fact that Robin's got a scan on her.

And… yeah, just wow.

‘…So, anyway. Hi.’

She blinks. Her eyes widen just a bit in what must be recognition. Recognition of a sort, anyway. The kind of recognition you get looking at the old mug shot of a minor interdimensional bank robbing alien whom you haven’t seen in three years or so. ‘Um…Hey.’ She mumbles, and Impulse’s hand goes for his hair and rubs. Rapidly. ‘Long time, no see?’

‘Longer for me,’ Impulse says. ‘Speed force time. It’s weird, though, so I guess it depends.’

Superboy casts a glance between them. ‘So am I… missing something, here?’

‘I dunno, where’d you see it last?’ her quip comes out of nowhere and sounds so much like something Kon would say that the boy in question chokes a little on pure air. Robin, for his part, doesn’t so much as twitch.

‘So, Imp, huh?’ she’s got her eyebrows raised and a grin on her face that reminds Kon of the Flash. ‘That what they call you round these parts?'

‘It's Impulse,’ Bart says, trying to do the whole I’m-a-hero-my-name-should-imspire-fear-in-the-evil-and-joy-in-the-innocent-so-don’t-laugh-damnit face. The newcomer seems no more weirded out than before.

‘Sure. That makes sense. Didn’t exactly expect to see you again, but then portals can be freaky like that. You never know where they’re gonna dump you next. Anyway the name’s Sparx.’

Impulse nods rapidly, thus increasing the confusion of pretty much everyone else in the room. ‘I know. You told me, remember?’

And now Impulse is starting to freak Superboy out ever so slightly… because he hasn’t moved from the spot for going on twenty-five seconds now, for one thing. Nor has he descended into random speed-freaking around the cave for another. In fact, the only movement he makes is one quick step towards the newcomer, who, in turn, steps back towards him. They’re right up close to each other and… she’s not quite as tall as she seemed on the Platform, but Impulse still has to look up at her a bit.

It takes all Superboy’s willpower not to whistle.

‘Man, Rob, whoever this chick is, the speedforce’s pretty much got her name on it.’

‘It’s not a chick, Superboy,’ Robin said, evenly. ‘It might look like one, but it’s not, I’m…’ he paused, and takes a while to actually admit it: ‘I’m not actually that sure what it is… it’s designed to be female, but it’s not. It’s not really anything. Just a bunch of coding.’

‘So… so you think maybe the speedforce made her? Maybe Bart's got some weird psychic thing goin' on with it, like when he makes those scouts.’

‘Negative, Superboy. I don’t think the speedforce made her; I don’t think she was even meant to be in there. It probably just acted as an unintentional conduit.’ Robin leaned back in his chair, shaking his head ever so slightly. ‘I don’t know how she got here at all.’

‘Oh, that’s easy,’ Impulse quips. ‘She got here by lightning bolt, didn’t ya, Sparx? You rode the lightning just like I did.’

‘Yeah I… guess… if that’s the only thing I could’ve done I guess I really must’ve done it. The portals must’ve been screwed up, though. I’m pretty sure I’m not supposed to be here. My friends will be waiting for me and… you know, my friends are big on timing. I don’t think they’d be too happy if I was late ‘cause I got caught up with you kids. No offence..’

‘We’ll try and do something about that.’ Rob says, obviously not making any promises and… what’s as he the only one in this room not looking at her because she’s hot?

And are those freckles? He digs the freckles.

But anyway -wow. Something Robin doesn't know. Now Kon just knows he's in some kind of Ttwilight Zone. But as far as things that aren't human go, this isn't exactly a bad looking specimen, and hey, it isn't like Kon had ever been picky about such trivial things as species.

Too bad she seems more interested in Impulse.

‘And you two… know each other,’ Robin adds carefully. Their response is a few short nods and a grin.

‘We met…’ Bart starts.

‘…In the speed force,’ Sparx finishes. ‘If that’s what you guys call it, I… well, it was kinda a long time ago, right, Bart?’ Then she smiles. ‘Yeah, that’s it… it’s Bart. I remember you telling me now. I knew it.’

‘Uh… Imp?’ Kon's confused (well, more confused than he already was) because his secret identity has just been blurted out by this… this thing that happens to be shaped convincingly like a woman, and Impulse being impulse, he should probably be having a minor streak out about it.

Except he isn't. He just looks at Sparx and grins and it's really like he trust's her, just like that. ‘Thanks, anyway. For saving my life and all.’

...Which would probably be something to do with that. And Kon gets the feeling this is a story he has yet to hear about and he's not going to to hear about anytime soon.

‘Thing nothing of it. A Lightning Knight doesn’t need thanking… anyway.’

‘Oh… so anyway, we’re even now, right?’

Lighting Knight?

Okay, and that sounded like something straight out of an eighties B-movie. Science fiction. With Meryl Strep or whatever her name was.

Sparx looks at him, and her blue eyes glitter… no, wait, not glitter, Kon realises –sparked. Like little lightning bolts. Like Bart’s. ‘Yeah, we’re even. Now, what’s this about a boom-tube bad guy? Might as well kick some butt while I’m here. You can show me the ropes, cool?’

‘Cool!’ Bart grins, and by the time Robin has looked up from the console and Kon has managed to think of another word for Impulse which isn’t “lucky brat” or “ladies' speedster”, the two of them have vanished from the room, and he’s not sure which of them was pulling.

Robin sinks a little deeper into his chair.

‘Uh... so, Rob. What was all that about?’