OCC: I am aware that this story uses a concept which is found in the recent fanfic story 'Flipsided' by betawho, and I would like to stress that this story is not a blatant steal of that concept. I've actually had this fanfic in my head ever since 'Time Crash' first appeared on our screens and became awed to the concept of what would happen if two of my favourite Doctors not only met but switched timestreams, forcing them to see their pasts once more or brave the uncertain days to come. I hope this story gives justice to the original actors and stories which inspired Time Switch into existence, and that fans of both the 5th and 10th incarnations of the Doctor will find something to like in here. I will stress that this story contains spoilers for many adventures of both Doctors, and in the case of the 5th Doctor and Nyssa, some of their adventures heard via Big Finish. So with all that in mind, I hope you enjoy the first installment of Time Switch! :)

PS. A zillion claps to fellow Who author Marcus S. Lazarus for his many suggestions on how I could get round some pesky Technobabble concerning the elements of this story. Thanks man!

In the depths of the Time-Space Vortex it sat brooding, its thoughts fixed upon the destruction of a single entity: the Doctor. Its forceful powers angrily probed the Web of Time, anxious to locate the threads and lines that only it could detect, here and there, determined to gain the power it so greatly desired.

It was the cursed Doctor's fault it was here since what seemed forever, stuck in the state of this formless larval state, trapped in the confines of the vast tubes and hives of all of Space and Time, yet completely incapable of moving anywhere through and out of them.

So much power at its flesh, and yet utterly no way of using it!

The creature screamed in frustration, bashing a horde of squawking Vortisaurs out of its path in mere spite. Like a tormented school child it marched forwards, little or no direction within its angered shove through the tunnels of the Space-Time Stream.

Curse the Doctor! We curse him forever! With silent screams of rage the creature once more hammered on the boundaries of the Vortex, demanding to return to the worlds it had once enslaved, once had under its thrall.

All because of the cursed Doctor!

In a moment which might have been the span of a heartbeat or a thousand lifetimes the creature slowed, turning from blind anger to a more calculated form of malice. It turned its head this way and that, desiring destruction and seeking the best means to escape its own prison of hellish nothingness.

The first thing that the creature noticed was the smallest of scents. A kind of light breeze it strained to recall. Then as its concentrated harder, the weakened mind remembered this scent, this form of prey. Anger resurged its mind to action as the larval creature pushed itself awkwardly through the Time Stream, feeling the scent drag ever closer.

Before long it was in its sights, pure and simple. The creature recognised the shape and structure – blue and cuboid with the hated letters which it had stored to memory.

Police Call Box! The TARDIS! The Doctor's TARDIS! Oh but this will be sweet revenge for me and all that I hold. To crush him in my tightest grip and before he dies, to know who and what strikes him down in the name of all that is evil in the universe! I will have revenge Doctor! REVENGE!

Emboldened to the prospect of killing so loathsome an enemy and to take him so quite unaware, the larval creature rushed forward as best it could, shortened yet still sharp fangs emitting from its throat, all thought fixed upon the blue box and the chance to kill its occupant.

So great then was its hatred and bile that it quite failed to trust its senses in full. Were the creature more tuned to its traditional cunning and wile, it might have considered the second blue box turning from just behind it, heading straight towards the first, identically similar blue shape that the creature was all but busy with, quite unaware of the larva simply because it would have been impossible for the ship and its occupants, a Time Lord identical and yet not so to the older and yet younger man living in the ship which had the creature's attention, and a woman from a dead alien world who had spent much time travelling with the man she knew only as the Doctor...

Inside the confines of the TARDIS this so-called Doctor, wearing his traditional yellow turn of the century English cricketer coat and hat, was busy testing gently the Central Console as it whirred happily down the by-lanes of the Space-Time Vortex, the interior of the vessel a brilliant white, dotted with hexagonal patterns within the walls of the ship and also containing an unused hat stand, several pot plants and a set of clocks within one corner.

The Time Lord gave a happy smile and sigh, clearly content with the current settings his TARDIS was registering for him. He looked about, wondering where Nyssa was at this time – his present one and only travelling companion, a member of the tragically fallen Traken, destroyed under the manipulations of his old enemy the Master. He'd had others before; men and women of similar backgrounds, and he was sometimes beginning to wonder if pulling such people into his world was potentially dangerous, even fatal to them. He and Nyssa were still grieving for the loss of Adric thanks to his relatively recent encounter with the emotionless Cybermen in a transport ship over 25th Century Earth.

It had been this tragedy, coupled with another battle against the Master on Prehistoric Earth which had seen the departure of another loved friend, the witty no-nonsense Tegan Jovanka, back into her life as a Flight Attendant on 1980's Earth and Heathrow Airport. He smiled slightly, finding it ironical once more that he had made several attempts to return her to her home time with minimal success – arriving three hundred years too early or late, or else another planet entirely. It was only an attempted trip to the Great Exhibition of 1851 in London to give Nyssa and Tegan an attempt to overcome the grief of Adric's death that he had, quite by chance, arrived smack bang where Tegan wanted to be.

In any case, she was gone from his life, and the Doctor continued to hope that her life had returned to some level of normality without him. In her absence though, life aboard the TARDIS had been quiet, perhaps uncomfortably so, and the Doctor had realised that he missed her answer back attitude greatly. Nyssa and himself had attempted to become occupied and in so doing had seen a great deal of the universe – fighting Daleks and their 'Mutant Phase' caused by a bizarre paradox on 22nd Century Earth; witnessing the origins of the Mondasian Cybermen in all too grizzly detail for his liking; meeting and being imprisoned by the cranky Isaac Newton; returning to Vortis and the Zarbi that he had visited so long ago in his original body; even discovering that Adric wasn't dead, but trapped in a parallel dimension for centuries, only to have to see the broken shell of a man who had once been such a close friend sacrifice himself once more to save him and Nyssa from certain death – more had happened to him in the last few months of his life than he cared to think about.

His sombre thoughts were interrupted as a red light suddenly flashed into life on the console his hands had been poised over, and a frown enveloped his otherwise youthful face. The beeping noise which emitted from the ship was unnatural to the vessel's typical sounds, and it was enough to get the attention of Nyssa, who moved out of the doorframe that connected the Console Room of the TARDIS from the rest of the ship, where facilities like the kitchens, wardrobe and bed rooms of his former and current companions could be found.

"I take it that that noise and accompanying sound suggests a problem, Doctor?" Nyssa spoke in a matter of fact tone, due in part to her high intelligence and understanding of the majority of the TARDIS' systems. The Doctor admired these aspects of her personality greatly, and was often aware that Nyssa was more than capable of understanding many of the more complex parts of the TARDIS and many long phases or commands he might have to throw out in the event of an emergency – which was too often for his liking. Regardless this made her one of his favourite travelling companions – a woman not tied to any one place (though in her case this was regrettably forced upon her) and more than a match for his levels of Time Lord Intelligence.

She was one of those few companions like Liz Shaw or dear Romana who played against type to the more common form of companion who might not understand quantum mechanics and be prepared to scream at the first green blobbed creature they encountered. Not that the Doctor minded such a companion if they were filled with the sense of wonder and fun of travelling the cosmos that he liked seeing in his friends – it was simply nice once in a while to have a wiser ally, particularly as Nyssa demonstrated the kindness and understanding his best friends in life had.

He answered her question hastily, anxious to avoid the typical responses that he would expect from Nyssa in such a situation. "To be honest I'm not sure Nyssa. It seems there might be some interference in the Vortex, something close to hand that the old girl doesn't agree with... Hmm, perhaps a look out is in order." He flicked a switch and the scanner buzzed into life, showing the swirling form of the Time Vortex; or to be more specific, a tunnel which connected some of Tegan home planet's near future – the first couple of years of the 21st Century - to the rest of Space and Time.

Nothing seemed inherently out of the ordinary. Several wild Vortisaurs were seen to buzz about the ship, sensing perhaps the juicy prize of the heart of the ship; raw temporal energy – yet completely incapable of getting into the TARDIS thanks to its high-tech defences. Besides, there were too few to pose any sort of threat which sheer numbers could produce.

"No, there's nothing out there I can detect to be causing that alert signal." The Doctor spoke with more than a hint of worry. He wasn't particularly keen on unknown factors, not in this specific incarnation. Perhaps his former body might have relished such a thing with a beaming teeth and curls smile, but not now. He pressed more buttons, trying to see if an audio feed would answer the questions which buzzed around in his head.

Nyssa looked back and forth between the Time Lord and the screen. "Well perhaps if you told me what that signal is meant to indicate, then I might be of better use. I know it's not the proximity alarm – I'm getting more than a little tired of primitive aerial vessels nearly hitting us, after all." Nyssa was, the Doctor knew, referring to the awkward incident of an airplane over Alaska even hitting them at the beginning of a rather exhausting adventure of some months past.

"Well Nyssa, there are certainly no planes in the Vortex here. It is funny though; that indicator is meant to show similar items but of an organically nature, but I don't think those small pack of Vortisaurs constitute that level of alert reading, do you?"

Nyssa turned to stare at the still flapping creatures that were moving away from them and the scanner image. "I still find it hard to believe that there are creatures who can survive the extremes of the Time Vortex."

"Oh, well the Vortex isn't exactly barren of life – I think our incursion in the Time Reef would attest to that. Ruhk, Vortisaurs, Reapers, the Eternals... not to mention the Chronovores, which I never like to dwell over very often... but no." The Doctor was carrying on flicking switches and buttons as the Vortisaurs moved further away from the ship.

Nyssa looked intently at the screen, and then gave a startled cry. Her head was aching painfully, a possible question of her telepathic abilities playing up once again, and hearing her distress the Doctor turned to her with a concerned glance. "Nyssa? What is it?"

The Traken woman seemed to have recovered, her headache failing slightly, but she still seem a little shaken. "I'm not sure, it was like for a moment I felt something out there, something angry – but whatever it was it seemed to vanish from my mind almost immediately." She gave a determined stare at the Doctor as he continued to look wary of her condition. "Really Doctor, I'm fine now – I think we should concentrate on learning whatever is spooking those Vortisaurs out there." Nyssa was right – the creatures were moving away from them at top speed, almost as if something had alerted them.

All at once there was a blinding flash, and the Doctor and Nyssa felt something rock the ship violently, sending them tumbling to the ground as the pair of time travellers struggled to get up with the sudden impact. Nyssa flashed a finger at the screen. "Doctor, look! There is something out there!" Sure enough a craft appeared to be moving towards them, distinct yet recognisable. Another wave of motion hit the TARDIS and the Doctor and Nyssa managed to just hold onto the console. "Doctor, what's happening? Is it some kind of temporal feedback?"

The Time Lord nodded. "Something the old girl really doesn't agree with – possibly whatever it was you felt for a second, or maybe something else. You know, that object in the distance is getting closer, I wouldn't be surprised if it was another Time Ves-"

The Doctor never had time to finish his sentence as there was yet another flash, the entire console room shaking and buffeting around Nyssa as she strained to cling onto the ship. In the back of her mind she thought she heard a familiar sound – a low dong which she recalled was the Cloister Bell, a noise the Doctor told her only ever went off when something was very wrong.

And then all at once, the noises and bright light quite abruptly stopped. Nyssa had been shutting her eyes tightly against the glare, so it was the lack of sound save for the console noises she recognised which got her attention. Cautiously she opened her eyes.

Dumb horror entered her brain. The room appeared utterly normal, even the Cloister Bell had stopped. But the Doctor was nowhere to be found. "Doctor? Are you there?" She called out, her noise avoiding any rash responses of fear.

No answer came. Nyssa became nervous under the damning fact that he had vanished. She glanced up at the scanner. It displayed the Vortex, quite unmoving. The TARDIS appeared to have stopped dead still in the tunnel. There was nothing outside that she could see – no Vortisaurs, no second ship approaching. Even attempting to strain for a feeling of the evil force she'd felt for a fraction of a second just before yielded nothing to her.

"Doctor?" She tried again. Still no response.

Then a noise got her attention. Small at first, a hissing snarl that developed into a roar, a primal beast's charging war-cry. Nyssa screamed painfully as she fell to the floor, her senses utterly overwhelmed...

The Larva had at first been confused at the sudden impact of metal and time just behind as it had strained towards the defenceless Time Lord just ahead of it. A new, younger scent had attracted its attention, similar and yet not so to the craft it sought to destroy

Then it took in the scent fully and a low laugh enveloped its body like a glove.

Two Doctors for the price of one? Oh delightful... Now this will be true revenge... And revenge is what I desire!

With a precise strike, the Larva creature wrapped itself round the two ships like a vice, anxious for the pleasure of torment for its most hated enemy to begin. It couldn't even begin to think what its influence would have on the destinies of those present.

It just wanted to see the Doctor suffer. And knowing the minds of each of him, the creature knew what to do to achieve its aims of revenge.

Revenge! Revenge against the Doctor! Revenge! Now and forever, revenge!

The Larva cackled as it pulled itself tighter round the ships once more...

"-essel out there... Nyssa?" The Doctor blinked as he became aware of a slight lurch in the pit of his stomach, a mild stab of pain in both hearts which eroded almost at once. But his attention was most drawn to the fact that Nyssa was missing.

The TARDIS controls beneath him gave a noise he recognised to be surprise, and quite used to displays of displeasure from the ship he called home, the Doctor became moving round the console, not at all noting his exterior surroundings save the absence of Nyssa "Right old girl, settle down-" His body impacted slightly against someone.

"Oh, excuse me." A voice at that moment the Doctor didn't register to be unknown to him; he simply nodded and carried on checking the TARDIS to learn the cause of the problem. Then the voice struck him like a hammer...

And then everything else around him.

The controls were completely wrong. The interior was utterly different – brown, coral like and far more vast than he was used to. And standing directly in front of him was a man in a blue pinstripe coat and suit with brown hair, staring equally surprised back at him.

"What?" The figure gave him a look of complete amazement, then a slight mixture or horror and perhaps amusement.

It took all his vast intelligence and conversational skill just to state the same two words as the pair sized each other up.

"What?"

DAVID TENNANT

PETER DAVISON

SARAH SUTTON

KYLIE MINOGUE

And starring JANET FIELDING as Tegan

DOCTOR WHO

Time Switch by Derek Metaltron