Earlier…

The Doctor knew something was up, even now.

He had been skirting around a little issue for a while, now. Charlie was keeping something secret from him – which the Doctor was determined to find out. All his attempts to uncover the truth had so far failed.

Now he was going to try a more direct approach.

Well, a subtly direct approach... in a roundabout way.

That thing with the kitten had been a minor distraction. (And so had all the other adventures, now he came to think of it). Now he could get back to the matter in hand.

Charlie was lounging in the Doctor's favourite leather chair on the upper level of the TARDIS console room, his nose in a book. A book he really shouldn't be reading, the Doctor reflected: for him, it hadn't been written yet.

Charlie was still, lost in his world, oblivious to the Doctor's restless pacing around the control room.

"Hmm…" the Doctor muttered loudly (no response), before wandering off.

He pondered on his problem as he absent-mindedly proved the existence of a new subatomic particle on the blackboard tucked away beneath the TARDIS console.

Charlie had started to open up more as of late, which was promising, but as soon as he was asked about the parts of his life from before they began their time travelling adventures, he would become somewhat cagey, giving very vague answers – often lies.

In many ways, the lies were a self defence mechanism – because lying was always easy. Particularly if you take the example of an 'I'm fine' when asked if you're ok.

But some lies can be dangerous. The Doctor had a feeling this was one of the dangerous ones. This seemed odd. Despite all the warnings Kate Stewart had sent his way, he didn't believe that Charlie was dangerous.

Perhaps he was hiding something that was. Whatever – or whoever – it was, he needed to know.

The Doctor resurfaced, drawing as much attention to himself as he could as he dashed back up the steps.

Ironically, the Doctor admitted, he was going to have to put on a bit of an act in order to coax Charlie into revealing his secret. Rule one and all that. Hopefully, the minor deception would be worth it, and dispel his fears.

"Where to go?" he said aloud, gesturing grandiosely – as he often did when posing a hypothetical conundrum.

"Always the problem, isn't it?"

The Doctor grinned, watching Charlie's eyes flicker momentarily from the book, only for them to be drawn back with some kind of magnetic force.

He raised an eyebrow.

"The TARDIS can go anywhere," he continued, "On the other side of those doors, is everything. Infinite worlds, in infinite time."

"I know that," Charlie uttered under his breath.

He didn't think the Doctor could hear him – but he'd forgotten how good these Gallifreyan ears were.

"21st Century Earth is quite nice, but it gets boring after a while."

The Doctor's hand curled around the brushed metal railing that led the way up the stairs to the upper level.

"And there's this patch around 2016-ish that I really like to avoid…"

He rushed up the stairs, pausing at one of the bookcases, a few feet behind Charlie.

He pulled out a random book. The Wizard of Oz. Fascinating story. Except it wasn't fictional – but that was a tale for another time.

"And you know what?" the Doctor resumed his spiel, sliding the book back into its place, and sidling closer to Charlie.

Leaning on the back of the boy's chair, he whispered:

"I can't make up my mind…"

Charlie paused, but pretended he was still reading.

The Doctor could tell that he was listening to every word. He hadn't turned the page in some time.

Backing away from the chair, the Doctor grinned. "I thought you could decide."

Charlie turned round, his eyebrows knotted. "Me?"

"Yes. You. Where do you want to go?"

The Doctor turned round, and skipped down the stairs.

His arm outstretched, he began to circle the TARDIS console.

"Where's the one place in the universe – in all of time and space – where Charlie Drake really wants to go?"

He stopped, thrusting his knuckles into the cold metal of the control panels. The Doctor leaned across the console, tempting Charlie with some enticing suggestions.

"The mystical moons of Caratian Four? The peaceful, yet technologically advanced world of Dymar?" The Doctor shrugged. "Or perhaps a jamming 'sesh' with David Bowie? Lovely man. Fabulous musician."

The moons of Caratian Four weren't that mystical. They vanished from time to time, but there was a perfectly reasonable explanation for that.

He could see the gears churning in Charlie's head. A number of expressions passing briefly across his features. Confusion? Concern? Excitement?

"What about that first one you said?" Charlie offered.

"No. No, no, no. Not where I want to go. Where do you want to go?"

"I – I don't know."

There was a strange tension in his voice. He did know. He knew exactly where he wanted to go. But where? And why? What was his plan?

"You could pick at random…" the Doctor tempted him.

Charlie's brow furrowed. "You can do that?"

"Oh yeah."

The Doctor pointed to the panel with all the orange goo in it.

"Stick your hands in there."

Charlie stood up, and edged closer to the console.

"What will that do?"

"It'll randomly pick out a location from all the places you really want to go to," the Doctor explained. "Even if you don't know what they are."

The Doctor gestured towards the panel again, seeing Charlie's hesitance.

"Oh. Okay."

Charlie tentatively pushed his fingers into the orange jelly – very cautiously, as though he was expecting to receive an electric shock.

Of course, the Doctor realised, he was expecting to receive a shock. Had the boy been sticking his hands in when he thought the old man wasn't looking?

The Doctor put his hands on Charlie's shoulders, hoping to reassure him.

"Now, concentrate," he urged, "Where do you want to go?"

Charlie's eyes were clamped shut, his eyebrows twisted in deep concentration.

"Let your mind focus on the moment. Picture the time, the place."

The Doctor peered at him. Charlie was silent – breathing a little heavily, but otherwise silent.

"You doing that?"

"Yeah…"

"Good. Keep doing that."

The Doctor ruffled Charlie's hair, encouragingly.

The action was largely ignored, which was just as well.

It wasn't a mere friendly gesture, but a ruse to plant a thought in Charlie's mind. A single psychic question projected to Charlie's subconscious: Who's Nate? Tell me the truth.

The Doctor pulled away, watching his friend intently, and slammed a lever on the TARDIS control panel. The engines roared into life; the resounding chorus of the TARDIS tearing through the time vortex reverberated through the console room.

"How long do want me to do this for?" Charlie asked, after a while. Neither of them had uttered a word in a few minutes. He had grown uncomfortable with the lack of words.

"Until I say."

"When will that be?"

"When we land."

Charlie nodded, adjusting his grip in the sticky fluid; the TARDIS trembled.

The Doctor counteracted by flipping a series of switches to stabilise the ship's flight path.

"Concentrate," he warned.

He checked the TARDIS' systems. The engines were still going. The Time Rotor rose and fell, pulsing with energy.

He had only used the new telepathic circuits a couple of times. They weren't always one hundred percent reliable, but still… twelfth time lucky?

Finally, the engines faded, grinding to a halt with a familiar thud.

"That's strange…" the Doctor muttered, pressing his fingers up against the swirling Gallifreyan symbols filling the screen, as he examined the space the TARDIS had materialised in.

"What's strange?" Charlie asked.

"That wasn't what I was expecting at all."

"How do you mean?" Charlie pulled his fingers out of the telepathic controls, and joined the Doctor by the TARDIS screen, wiping his hands on his hoodie in disgust.

"Well, we've landed, but I don't recognise the coordinates. Do you?"

Charlie looked at the swirling arcs and hexagons swimming around the screen, and turned to the Doctor.

"I can't read that."

"Ah yes."

The Doctor pressed a button on the console.

The circular symbols were replaced with a series of numbers, superimposed over a scene of space outside the TARDIS doors.

Charlie seemed distracted by the dancing purple formations, reminiscent of some kind of squid, its tendrils flicking out across space.

"Recognise it?" the Doctor asked.

"No."

"That is odd, for the one place in the universe you most want to go," the Doctor mused.

"I guess?" Charlie nodded at the picture. "Looks pretty, though."

"Pretty…?" The Doctor peered back at the screen, and took a second look at the shimmering patterns unfolding across the TARDIS monitor. "Yes, I suppose it is."

The Doctor tapped at the purple squid.

"You know, that looks a lot like the Jagarovian Nebula."

"So you do know it?" Charlie teased him.

"I know of it," the Doctor admitted, "I've seen pictures. But I've never been here before. It's a long way from home. From both of our homes."

Charlie shrugged. "If you don't like it, we could always try again? Go somewhere else? I don't mind."

The Doctor peered at the boy for a moment.

"Are you serious?" he exclaimed. "You've chosen this place – here, now. And neither of us knows where it is. Doesn't that fascinate you?"

"Of course it does." Charlie faked a grin. "Just not what I was expecting, that's all."

Charlie's melancholy gazed locked onto the serene scene of space on the monitor.

Okay, he wasn't lying, then.

"Shall we take a look?" the Doctor suggested.

"Yeah."

"Awesome!" the Doctor grinned, heading for the door.

"Hold on," Charlie uttered. He backed up against the TARDIS console, a bemused look upon his face.

The Doctor stopped, throwing Charlie a confused glare. What now?

"Did you just say... 'awesome'?"

The Doctor frowned.

"I, uh… might have done…"

Was he going a bit far with the false enthusiasm? Was Charlie cottoning on to his game plan?

Charlie chuckled, pulling his phone out of his pocket.

He bit his lip, noticing something on the screen, and peered over at the TARDIS console.

Finding what he was searching for – to the Doctor's amazement – Charlie plugged his phone into a charging socket in one of the control panels.

The Doctor raised his eyebrows. He could have sworn that the socket hadn't been there before.

Seeing the Doctor's bewilderment, Charlie explained: "The battery's low."

"Right…"

Deciding that he didn't care about trivial human matters like phones and social media, the Doctor turned his back on the console, and swung the police box doors open. It was dark outside. Even the light from the TARDIS seemed to be swallowed up by the space beyond the doors.

There could be anything out here. There was a distinct feeling of dread creeping in through the TARDIS doors, and it made him a little apprehensive.

For once, the Doctor didn't feel that stepping blindly into the darkness was a good idea. He took out the sonic screwdriver.

He adjusted some settings, twiddling with the mechanism, until the red metallic emitter ring folded away; spinning gyroscopically as the LED was reinforced by far brighter lights.

He directed the powerful torch beam outside, but it had no effect on the wall of darkness outside the TARDIS.

"It's dark," Charlie commented.

"It's funny, but I had noticed that," the Doctor muttered, stretching his arm out into the darkness. His arm - and the screwdriver - virtually disappeared.

"There is definitely something here?" questioned Charlie. "There isn't just, you know, nothingness?"

"Let's find out," the Doctor replied, "Shield your eyes."

Charlie did as instructed, and the sonic issued an intense flare – brighter than a sun.

It took Charlie a few moments to recover from the sudden flashbang, but the Doctor had already memorised an image of their surroundings revealed by the split-second of light.

"I don't recognise this place," the Doctor muttered, "Not at all."

He pulled the sonic back into the light of the TARDIS, and scratched his chin.

"I didn't see anything," Charlie admitted.

"It's old," the Doctor stated. "Primitive, almost."

"No light switches, you mean?" Charlie quipped.

"I wouldn't say that," the Doctor muttered with a smirk, and waved the sonic in the manner of a conductor's baton.

Something glowed red-hot in the space ahead, and burst into flames.

There was a rusting iron brazier in the centre of the room outside; the fire bathed the surrounding chamber in a warm, orange light. Flickering shadows played upon the stone slabs covering the floor, obscured beneath a thick layer of moss. Figures danced across the cracked walls, distortions of the metal creatures caging the fire.

The TARDIS had landed inside some kind of derelict temple – left abandoned for centuries.

Charlie poked his head out of the TARDIS door.

The walls towered over them, seeming vast, yet claustrophobic at the same time.

The chamber was massive; the floor spanning about half the size of a playing field.

The Doctor was already skirting around the walls, igniting flaming torches with dainty flicks of the sonic.

Charlie pulled the door of the police box shut, and inspected the central fire. Six iron snakes, blackened with soot, twisted their way out of the ground, dancing around the flames.

The yellows, reds, and oranges circled around, flickering fiercely, lashing out at the serpents. Charlie found the fire drawing him in, hypnotising waves of warmth and light enticing him nearer to the crackling flames.

"What do you think?" asked the Doctor, wandering the room, inspecting the walls, as though he were meandering through an art gallery, not an alien temple.

Charlie shrugged. He wasn't sure how to explain the feelings he had. "I was expecting something a bit more…"

"Something a bit more exciting?" the Doctor suggested, his eyebrows twisting excitedly.

"Yeah," Charlie agreed, "Something less…"

"Boring?"

"Well, yeah."

"You're right!" the Doctor called out at the bare stone walls. "There's nothing here. No doors. No windows."

"No doors?" Charlie pondered.

The Doctor turned to him, a smile creeping across his face. "Oh – very good!"

"There has to be a door somewhere," Charlie reasoned, crossing the room to stand by the Doctor's side. "This can't just be a place no-one can get into."

"Probably. Although, not every creature in the universe actually needs doors."

"Well, that's…"

Charlie was silenced by a deep rumbling noise. Two gigantic archways rolled open, severing the stone walls in two.

"Ohh!" the Doctor roared in awe. "Automatic doors! An advanced civilisation, then?"

Charlie sighed.

How many times? Automatic doors were not a sign of advanced society. Although these doors were made of solid stone, so it was pretty impressive, all things considered.

"Ah, look! Door signs," the Doctor uttered, gesturing towards a tableau of engravings that had been revealed in the sides of each archway, at about shoulder height.

The etchings were subtle, barely noticeable among the stones due to centuries of erosion.

The Doctor bent over to examine the patterns, his nose hovering inches from the stone.

"What does it say?" Charlie asked.

"I have no idea. I can't read it at all."

The Doctor glared at the stone, daring the engravings to torment him further.

"I thought the TARDIS translated everything."

"It has," the Doctor muttered, his fingers tracing the bumps in the wall. "But it's still too complex for me to understand."

Charlie almost laughed. "Really?"

"If I didn't know better, I'd say this was the exit."

"Oh, good," Charlie acknowledged brightly, nodding energetically.

"Boring," the Doctor corrected him.

Charlie followed the Doctor as he dashed over to the other archway, and began meticulously studying the engravings there instead.

Charlie wasn't sure what the differences between the two were.

"You have a go. Feel that." The Doctor tapped the inscriptions, so Charlie reached for it. He ran his fingers across the smooth stone, feeling the pattern of the engravings rise and fall beneath his skin.

"Oh, is it like braille?" Charlie realised. "Sensory writing?"

"Yes, very much like braille," the Doctor agreed sarcastically, "In the same way that two tin cans tied together with a bit of string is like an iPhone."

"It's three dimensional, in simplest terms," the Doctor explained. "It appears to be a language based on feel, and energy."

"That sounds a little vague."

"Yet it allows far more precision and distinction in tone than any of our dialects," the Doctor argued.

"Still can't read it though," Charlie countered.

"Never say never," the Doctor protested, maintaining an air of dignity and wisdom, "I think I can decipher it, but it'll take time. I'll scan it with the sonic, and leave it running a translation algorithm."

The sonic buzzed, casting a harsh glow over the rock.

"Judging by the larger volume of characters, it's offering a more detailed description. Directions, perhaps. Which leads me to conclude that this doorway leads us deeper into this place."

"I wonder what it really says," Charlie mused, "Knowing our luck, it probably says 'danger: keep out'."

"This is a sacred place of worship – do not touch the artefacts," the Doctor joined in.

"Private property, no trespassing," Charlie added.

"Pete woz 'ere." The Doctor grinned childishly, and tapped the sonic again.

"Anything?" Charlie asked.

"Not much," the Doctor conceded. "I've got the gist of it."

"Go on…?"

"There's energy here." The Doctor's eyebrows shot up.

"What? Something else?"

"That energy…" the Doctor muttered, slowly, hesitantly. "Feared and revered… It's a temple – a place of worship. A shrine of some kind."

He turned to Charlie, his eyes suddenly deadly serious.

"This place has a secret," the Doctor uttered, his tone grave. "Seen only by those who dare to find out."

He was silent for a moment – but that stillness vanished as the Doctor grabbed one of the burning torches, his restless energy reignited once more.

He brandished the torch ahead of them, pointing into the darkness beyond the archway.

"Want to find out what it is?"

"Oh yeah!" Charlie grinned.

"So do I," the Doctor muttered under his breath, taking one last look at the TARDIS as he crossed the threshold.