The Doctor shifted the stethoscope around the surface of the bubble containing all of Charlie's thoughts and memories.

He listened intently to the murmur of voices and sounds, like a safebreaker cracking open a vault, until he came across the thing he was searching for. That name again, whispered in a dream. Nate.

"Who is he?" the Doctor wondered. "Who's Nate?"

He continued eavesdropping on Charlie's life. Any further mention of the name was immediately followed by a furious hiss of static. His search was yielding no results. Charlie had locked him out.

The Doctor pulled away, and stared at the glimmering bubble, puzzled.

"And more importantly, why don't you want me to know?"

The Doctor thumped his forehead. "What have I missed? What else have I seen that doesn't make sense?"

He pondered on this for a moment, recalling snapshots of their adventures. Charlie asking him all those questions in a playground, whilst the Doctor busied himself with a less-than-successful contraption. Charlie in the Observation Deck on the UNIT Moonbase, before he was captured by the Arachnids and presented to their queen.

He whirled round, pointing suddenly at the bubble and roaring: "The Arachnid Queen! You defeated it."

The Doctor frowned, glaring at his reflection in the shimmering orb. Or it might have been Charlie's memory of his face. Did he always look that grumpy?

"You must have defeated it. Because somebody did, and it wasn't me."

The Doctor concentrated, probing Charlie's memory of the event for an answer.

The Queen lunged at the Doctor. He had dodged all of the monster's attacks this far – but his luck had run out. This time, he was too slow.

The Arachnid sank her fangs into his arm, and the Doctor gasped – and crumpled to the floor.

Charlie couldn't move. He was trapped – bound in the Arachnids' webs. The sensation of a million unhatched spiderlings churned in his stomach.

He was watching in horror, praying for the Doctor to get up – to show some sign of life. But there was nothing.

Pure rage flooded through his mind. The Arachnid Queen scuttled around, flecks of venom spitting from her vicious fangs.

Just as the Arachnid was about to strike, she stopped, and backed away, quivering, curling up into the smallest size possible.

And then -

Nothing.

That was it. That was all Charlie remembered. After that, he must have blacked out, or forgotten.

"That doesn't make sense," the Doctor whispered. "You stopped the Arachnid Queen – but you don't know how?"

The Doctor frowned, as his exploration led to a discouraging development. There was a thin wisp floating inside the bubble – exactly like one of the dark shapes pounding on the outside of the bubble.

That meant only one thing – something had found him.

"I've been here too long," the Doctor realised.

He opened his eyes. He was back on the Time Lords' ship, in the middle of a warzone.

Back to the TARDIS. Without a doubt, it was where Charlie would have gone.

This nightmare was at its close. Very soon, he would be torn away

He began to run, shoving his way through confused Time Lord soldiers. He didn't have time for them. He needed to find Charlie before it was too late.

Charlie coughed, and spluttered, and immediately sat bolt upright.

He was somewhere new. Still inside the TARDIS, but he had no idea where.

Not again. Was he ever going to get out of this endless maze?

He stood up, exhausted.

He brushed the straw and dust from his clothes, and took a deep breath.

Find the Doctor. Find the Doctor, and save him.

That was all that mattered right now.

Charlie wasn't sure how long he walked for. Every stretch of corridor looked the same.

What he did know was that the soles of his feet were beginning to ache, and blister.

In a dream, time is not relative. Days pass in minutes, seconds last for eternity.

And sometimes, you find yourself somewhere with no real knowledge of how you ended up there.

One moment, Charlie had been walking past a swimming pool – which didn't look like it belonged inside the TARDIS at all - and the next, he was standing in front of a door. A plain metal door, just like all the others along this corridor.

At his feet, lay a welcome mat, which read: 'go away'.

It was weird, and so passive-aggressive, it had to be Doctor's.

His heart pounded – had he finally found him?

He was about to push the door open when someone tapped him on the shoulder.

He span round.

"Doctor?" he uttered in disbelief.

The Doctor grinned.

"There you are, Charlie. I've been looking for you."

"But…" Charlie struggled to question him; his relief at finally finding the Doctor eclipsed everything else. "What happened? Did you save her?"

The Doctor threw him a puzzled expression. "Who?"

"The old woman. Mrs Madigan. The one from the orphanage?"

The Doctor's eyes lit up, as he remembered. "Oh, yes. Her."

His features dipped back into a frown. "No."

"Oh…" mumbled Charlie. "But we can still save you, right?"

The Doctor held out his hand. His veins were visibly pulsing with a dark green fluid.

"I don't know. Time Lord biology is very complicated."

Charlie clasped the Doctor's hand, examining it. His skin felt dry; cracked and cold. He did not look healthy.

The Doctor's eyes flickered up to him, and he sharply withdrew his hand. "I have a question for you."

Charlie looked up at the Doctor's glowering expression.

"Why are you trying to save me?"

He seemed genuinely cross with him. As though the fact that Charlie was trying to help him irked him somewhat.

The corner of Charlie's mouth twitched.

"What… what do you mean why?" he managed.

"I think it's a fairly obvious question," the Doctor growled.

"I think there's a fairly obvious answer!" Charlie retorted, quickly taking a defensive stance.

"Which is…?"

The whites of the Doctor's grey eyes were shining with fury. Charlie couldn't understand it.

"Uh, because I'm lost in the TARDIS, and – should I ever find my way back to the control room - I don't know how to fly it?" Charlie uttered in desperation, "And… I really don't want you to die!"

He wasn't lying. Honestly, he wasn't. Why couldn't the Doctor see?

The Doctor's scowl softened. "Oh, that's very nice of you."

He clapped Charlie gently on the shoulder, and bounded away down the corridor.

Charlie's jaw dropped.

"Okay…?"

He wasn't sure what had just happened, but he was willing to go with it – as long as the Doctor was back – and dashed after him.

"How to save me, then," the Doctor mused, as they walked.

Charlie wasn't sure where they were heading, but the Doctor seemed to know his way.

"If I could jump start the regeneration process, I might yet survive. But first, we need to find the source of the Arachnid venom."

"The source?" questioned Charlie. "But I thought the Arachnid Queen was… destroyed?"

"No." The Doctor frowned, his attention snapping back to Charlie. "No, sorry, yes, the Arachnid Queen was destroyed. But the venom is still spreading. I can feel it growing darker every minute. Which means the venom is being fabricated somewhere in my body."

The Doctor rubbed his chin, lost in thought. "That's actually a really clever mechanism…"

There was a clang, echoing from the corridor ahead of them.

They stopped, and waited.

Silence.

"What was that noise?" Charlie asked, in a far higher-pitched voice than he intended.

"I don't know. But considering every other noise I've heard so far has turned out to be a hideous nightmare, it's not looking promising," the Doctor muttered.

"Great…" Charlie groaned, staring pensively into the darkness.

Their shadows seemed to dance; dancing the dance of despair. Imaginary shapes swirled as his eyes struggled to make sense of the dark.

He heard the noise again.

Clang!

Something was coming; edging, shuffling along the TARDIS corridor.

And the Doctor was waiting for it, an ominous glare on his face, willing the darkness to do its worst.

"Are you scared?" the Doctor suddenly asked.

Charlie looked up, into the Doctor's piercing glare.

He had had this revelation before. The Doctor had this presence. Whether it was wisdom, or pure determination, Charlie felt safe by his side. If the Doctor was there, he was going to be okay.

"No," Charlie answered.

"Then you're an idiot," the Doctor muttered sharply.

"Thanks…" Charlie grunted.

Clang! Thump!

Whatever this thing was, it was coming closer.

All Charlie's instincts were screaming at him to run. He tried to move, but the Doctor grabbed his hoodie, holding him in place.

"That's incredible," the Doctor uttered.

"What is?" Charlie glanced around. The Doctor had seen something, but he had no idea what.

"There's nothing there," he pointed out.

The Doctor shook his head, reaching out with his other arm to point at the corridor.

"Look at the floor."

"Oh!" Charlie retreated slightly when he saw what the Doctor was pointing at.

There was a shadow creeping across the floor.

It looked to be a humanoid figure, shuffling slowly towards them.

But there was nothing else there – nothing which could be casting that shadow.

"Don't let the shadows touch you," the Doctor hissed.

Charlie's skin crawled. He was itching just thinking about all the terrible things that could befall him.

"Why? What'll happen?" Charlie asked.

"Don't get caught up in the details," the Doctor retorted, "Just don't let them touch you!"

"Okay, okay, I get it."

He was sure the Doctor knew what he was doing, but nonetheless, he was starting to get a little edgy about the Doctor keeping him pinned in place.

The creeping shadow stopped, a couple of metres from them.

The Doctor, lips pursed, silently pulled the sonic screwdriver from his pocket.

He pointed the device at the shadow; the screwdriver hummed.

The shadow evaporated into a mist. Tendrils of wispy smoke swirled around each other before transforming into an ethereal figure.

It was weirdly distorted, but definitely a person, with a ghostly visage and strange, loose clothing, which seemed to be floating – lighter than air – at the extremes.

The clothes were familiar, but Charlie couldn't think why. They were old fashioned: a waistcoat and jacket, with a large collared shirt and chequered trousers.

"What is that?" Charlie whispered.

The Doctor's eyebrows twitched; his screwdriver still outstretched.

"The same as the others, I imagine," he muttered.

Charlie frowned. As he was about to question what the Doctor meant, he was released from the Time Lord's grasp, and they both turned around.

There were more shadowy figures behind them – half a dozen at least.

"Woah!" Charlie took a step back, but remembered that there was one behind him, and returned to the Doctor's side.

"Who are they?"

The Doctor peered at them in horror.

"They're… me."

Charlie shot an incredulous glance at him. "What do you mean, they're you?"

"They're my other selves. Twisted shadows of my former lives."

Charlie looked more closely at the figures, and realised what the Doctor meant: the shadows, although faceless entities, wore the garments belonging to the Doctor. Long scarves, trench coats, braces and bowties, leather jackets and… and was that a stick of celery?

He wasn't sure exactly how he knew this, but these were clothes that the Doctor used to wear, when he was… someone else?

"Regeneration…" Charlie breathed in realisation. "This is when your face changes after you die? You were trying to tell me about it before."

"My entire body changes," the Doctor corrected him, "Every cell is renewed. My DNA is re-coded. I become a completely new man."

They twisted round, trying to keep back from the shadows slowly advancing towards them, ghostly limbs outstretched.

"Are these real?" Charlie asked.

"That depends."

"On what?"

"On what reality is."

Charlie paused for a moment, trying to work out what the Doctor was telling him. "No, I don't get you."

"Reality is just an illusion," the Doctor explained, "Everything you think you see is simply what your mind stitches together."

"So…"

"Sight is just one of the ways you make sense of the world."

The Doctor locked him with a fierce glare. "There are more sensory stimuli in the universe, and in my head – which you're filtering out simply because you don't have the capacity to perceive them."

After a moment, Charlie broke away from the Doctor's gaze.

"Okay, no, I don't like this. Stop making my question my existence."

"These are four dimensional entities," the Doctor growled, throwing his arm towards one of them, "They're not existing now, relative to us. They're in the past… the future…"

"But they can still get us, right?" Charlie asked, dreading the thought that he had already guessed the Doctor's response.

"Of course they can."

Charlie gritted his teeth, as he watched one of the shadow Doctors reach towards them, its arm passing through one of the others. As it stepped through its ghostly counterpart, the air crackled with static; Charlie's hairs on his arms and neck stood erect.

As he watched this shadow with increasing fascination, he noticed that there was something different about it.

"Uh, if they're all meant to be you, then… who's she?" he asked the Doctor.

"Shh!" the Doctor hissed. "Spoilers!"

Charlie immediately clamped his mouth shut.

There were more questions he wanted to ask, but his automatic response to the Doctor's command had silenced him.

Besides, it wasn't important right now. He could file it under 'things to think about when you are not being chased by monsters'.

Right now, they needed an escape.

Charlie twisted round, searching for an exit which wasn't cut off by a shadowy figure.

The Doctor noticed him, and threw him a wry smile.

Charlie found his apparent lack of concern wildly frustrating, and he had to suppress an urge to scream at him to help find a way out of this.

Of course, the Doctor had a reason for his smug grin.

"There's another way out," Charlie realised, studying the Doctor's facial expression. "Where?"

"You're looking in the wrong direction," the Doctor hinted.

Charlie peered through the ethereal figures – but he couldn't see a way past them.

After a few moments, it dawned on him.

He looked up. There was an aperture in the ceiling above them.

The sly devil…

"How do we get up there?" Charlie asked.

The ceiling wasn't that high, but it was still further than either of them could reach. And with a horde of shadows closing in on them, they didn't have much time to think of a solution.

"It's okay. We're standing on an elevator," the Doctor assured him.

"Wow. Really?"

The Doctor answered Charlie by flicking on the sonic screwdriver.

The corridor, and the shadows, around them fell sharply away.

The aperture twisted open, like a metal iris.

They burst through onto another level, and the Doctor clapped his hands together in delight.

So this was why the Doctor had kept him pinned in this spot – it was their only escape route.

"There you go, Charlie," the Doctor lectured him, "That's the secret to surviving in this universe. Always have a cunning and overly theatrical escape plan."

"Sure…" Charlie uttered.

The Doctor's triumphant exit was short-lived, however. Moments later, the shadows began seeping up through the floor panels.

To these creatures, 'up' was not a direction which hindered them.

"Uh, Doctor…?"

"When I say run, run," the Doctor whispered.

"Why don't we just run now?" Charlie exclaimed.

The Doctor threw him a thoughtful glare.

"Uh… yeah, go on then."

The dark wisps billowed out from the gaps in the floor grating, and began materialising into Doctor-like forms once more.

Charlie didn't hesitate to watch; he turned and bolted.

As they raced down the TARDIS corridors, Charlie's mind drifted back to the first time he and the Doctor ran. That panic at being chased by terrifying monsters, still fresh as ever.

Unlike that first time, however, his legs were holding out. Who knew that running from deadly dangers could be such a workout?

"In there," the Doctor yelled, his arm outstretched, pointing towards another identical door.

The Doctor practically shoved Charlie through the doorway, and heaved the heavy bulkhead closed behind them.

The sonic fired up, and the door's deadbolts slammed shut.

It was a very deliberate, final sound – as though this exit was now permanently sealed.

"We should be safe in here," the Doctor muttered, breathless, shoving the screwdriver back into his jacket pocket, and leaning back against the deadlocked door.

Charlie wasn't sure that a door could keep the weird time shadows out, but hey, the Doctor seemed confident that it would. That was good enough for him.

Author's Notes:

I realise the resolution of the last adventure wasn't really-

Trdpcbrf. Jpkd pm! Ejsy'd jsoowmws?

++INCOMING MESSAGE++

There we go. That's enough of that. No-one wants to hear about all this. I think I'll take over now.

Ah yes! Reader. There you are. I've been waiting for you. Don't worry, it's nothing sinister.

Who am I, you might be asking? Actually, you might not, but I'll tell you anyway.

I am known as the Voice of Unreason. Yes! I quite like the sound of that.

Seeing as how you're invested and such (I mean, you're still here), I might as well take the opportunity to do my thing.

You know, just being a nuisance and stuff. I am the author's nemesis, much like the Master is the Doctor's enemy.

So I'm here to undermine things, and add a bit of culture and gravitas to the proceedings. Sort of an experimental thing, if I'm honest. Just in case this tale of heroics, grievances and getting lost inside the Doctor's mind wasn't enough.

Spoilers: the Doctor dies. But then you already knew that.

Sorry for the author's long chapter, have a Sontaran.

Sontar-Ha!

++ADDITIONAL MESSAGE++

Actually, I'm just messing. I have no idea what will happen to the Doctor and Charlie.

I'm just a fourth wall breaking character. (Do fanfics have a fourth wall?)