Simmons led the Doctor and Charlie to the powerhouse of sector seven, somehow managing to keep up the Time Lord's speedy pace, whilst explaining one of her research discoveries to him.
The Moonbase was quite a large construction, and from what Charlie could gather, consisted of nine sectors, each branching out from the central command hub across the lunar surface. Some of the architecture was not consistent, and sector seven seemed a relatively recent addition to the Moonbase. It seemed a little more homely – if that was the right term. The floor was carpeted, rather than naked metal. There were less specialised laboratories. Instead: meeting rooms and lecture theatres. Perhaps UNIT had installed a training facility here for new recruits. It was an interesting idea, Charlie thought – imagine going to school on the moon!
Simmons eventually showed them into what was essentially a walk-in cupboard. The poky space was crammed with industrial-scale computers and generators, which all seemed to be humming and blinking satisfactorily. It seemed incredible that this tiny room was partially responsible for providing power for the whole sector.
There were two technicians examining the machinery; they had been accompanied by trio of guards wielding assault rifles, who were keeping a watchful eye from outside the room.
One of the technicians grunted in frustration, and threw down the electrodes, with which he had been tentatively prodding the terminals of the machine to take readings.
"I don't understand it," he whined, sharing a defeated look with his equally baffled colleague.
"Let me guess," the Doctor interjected, stepping forward and poking his nose at the machinery, "Everything's working fine – better, in fact."
The technician glanced up in astonishment. "Yes, that's right. But that's impossible."
"Nope," the Doctor countered. "It only seems impossible for a tiny human pudding-brain like yours."
The technician's mouth fell open in affront. "I…" he gasped, scratching his balding head.
There was a sense of unease for every human in the room, who were all somewhat offended by the Doctor's remark.
The technician looked the Doctor up and down, as if trying to distinguish his qualifications from his appearance, and his eyes opened in sudden realisation.
"Oh, I see. You're the Doctor. I've 'eard about you," he muttered disapprovingly.
The Doctor flashed a confused grin, and quickly returned to his inspection of the machinery.
"He's changed a bit since I met him," Simmons whispered to Charlie.
"Has he?"
"Yes. He never used to be this rude."
To the horror of the technicians, the Doctor began to pull thick tangles of wires from the computers, and left them trailing across the floor.
Charlie and Simmons shared a startled look, but they let the Doctor get on with his mutilation of the machinery. They both knew him well enough not to interfere when he was being 'clever'.
"This is impressive," the Doctor admitted, examining readings from the sonic screwdriver.
Charlie stepped forward, and peered into the jumble of cables and circuit boards.
"What is?"
The Doctor removed a chip from the computer, the size of a postage stamp, and held it up under the harsh strip lighting.
"These microprocessors are far faster than they should be. Humanity isn't capable of configuring technology this powerful for at least another two decades."
"What are you saying?" asked Charlie. "That this is from the future?"
The Doctor shook his head. "No, not at all. This is contemporary. But it's been altered, and pushed to perform beyond its original capabilities."
"So it isn't an act of sabotage, then?" construed Simmons.
"I don't know," the Doctor growled. "But I have a suspicion that the entirety of the Moonbase's systems are being tampered with, and rewired, bit by bit."
"So someone, or something, is taking over the base?" concluded Charlie.
"Yes. Quite an efficient takeover, too," appraised the Doctor.
"Doctor?" asked Simmons.
"Yes?"
"If the base's being taken over, as you say, then what about life support? What if that's been affected, too?"
The Doctor pointed at her, his lower lip curling between his teeth in an acknowledgement of Simmons' sensible suggestion.
"I'll take a look at it, but we'll just have to hope that whoever is responsible also needs life support," he answered.
"And if they don't?" asked Charlie, instantly regretting his decision to speak. He wasn't sure he wanted to know the answer.
"Then we pray they want to keep us alive," the Doctor said simply.
Charlie felt cold, all of a sudden. Being in a building, isolated on the surface of the moon – where there was no oxygen – felt incredibly vulnerable and claustrophobic.
"Doctor," called one of the security guards, "we've found something."
Without a moment's hesitation, the Doctor dashed out of the room to investigate. Charlie barely had time to register his movement before darting after him.
The three guards were hovering in the doorway to a nearby storeroom, shining torches into the darkness. They seemed a little apprehensive, and gladly stepped out of the way to allow the Doctor through.
The first thing that struck Charlie was the stench.
There was something decaying in here; the smell forced its way down his nose and throat, and Charlie had to fight the impulse to retch.
There were rotting carcasses of meat splayed across the floor, the flesh charred and corroded; the remaining flaps of blood-red skin sagging over the ribcages.
As Charlie inched closer, he realised he could make out some of the features of one of the carcasses. The creatures were warped; heavily disfigured by swollen, black pustules. But beneath the distorted, decomposing matter – a face. A human face. They were people.
Charlie backed up against the wall, a feeling of nausea sweeping over him once again, as his knees threatened to buckle.
They had been burned, and mutilated. Their internal organs were no longer recognisable. Whatever was left of them was oozing out into a puddle on the floor.
"Oh my god…" gasped Simmons.
"What happened here?" the Doctor demanded.
The stony faced sergeant shook his head. "I don't know. We just found them like that. It looks like some kind of… acid attack."
The Doctor crouched down carefully beside the bodies, studying the remains with lurid fascination.
"No…" he breathed. "It's like they've been dissolved… digested."
"What could have done this?" asked Simmons, who was keeping remarkably cool, despite the dreadful scene presented to her.
The Doctor looked up at her, clueless as to an explanation.
"What do you think, Charlie?" the Doctor asked, casting a sorrowful glance over the corpses.
"I don't know," Charlie grunted. "I do know that I'm… very probably going to be sick."
The Doctor glanced over at Charlie, and leapt up when he caught sight of the boy's pallid demeanour.
Charlie almost heaved, and desperately fought against a burning sensation, clawing at the back of his throat. He quickly placed his fist over his mouth in anguish, and struggled for a breath. However, the unpleasant stench filled his lungs once more – making things much worse.
"Ah…" the Doctor shook his head, grounding his thoughts. "Sorry, Charlie, I forgot. Perhaps it would be best if you, uh… went back to the command centre."
Charlie staggered out of the room, grasping the doorframe for balance.
"Could someone take him?" the Doctor asked, glaring at the security guards.
"I'm pretty sure I can find my own way back," Charlie protested.
"I don't doubt that. But I do, however, doubt you can defend yourself against whatever is capable of this." The Doctor gestured towards the liquefied bodies, and Charlie was forced to agree.
The soldiers exchanged glances, and Charlie was pretty sure they were silently deciding who would be burdened with babysitting the kid.
The youngest of the three men volunteered, and clapped Charlie on the shoulder. He did not, at least, seem too keen to hang around here.
The Doctor waited until they had gone, before conducting a brief autopsy.
"Did you say… digested?" asked Simmons, crossing her arms, and leaning closer.
"It certainly seems that way," the Doctor replied, gesturing towards a cluster of boils and blisters seeping yellow pus. "Digested externally, and then consumed."
"They were eaten?" the sergeant asked.
"Yes," the Doctor replied tersely.
"So we're under attack from aliens that eat people?" he continued.
"That is the obvious conclusion," the Doctor grumbled, shooting the sergeant an irritated glare.
"Then…" the sergeant began.
"May I borrow your bayonet?" the Doctor interrupted him, thrusting out his palm.
The sergeant passed the blade to the Doctor, with an air of mistrust.
The Doctor prodded the viscous pus dripping from one of the carcasses, and scooped up a globule on the end of the bayonet. He sniffed the substance, and recoiled sharply from its foul tang.
"This is unusual," the Doctor commented.
He peered up at Simmons. She seemed equally intrigued by the foreign substance.
"I'd like to run some tests on this," the Doctor muttered.
"Then we can take it back to the lab," Simmons responded enthusiastically, producing a test tube from her lab coat.
The Doctor was impressed by her resourcefulness, and spooned the cloudy fluid into the tube.
"Be careful with that," the Doctor warned her, as she placed a stopper on the glass phial.
Simmons cast a nervous glance over at the corpses.
"Oh yes, I will."
The Doctor returned the bayonet, wiping the blade clean on the sleeve of the sergeant's jacket, before handing it back to him. The sergeant accepted the blade, a grimace of disgust slipping past his stony features.
The Doctor stood up, wiping his hands on his lapels, and cast another remorseful glance over the room, before stepped outside.
"You," the Doctor expostulated suddenly, whirling round, and pointing at the sergeant. "Stay on your guard here. The assailants can't have gone far. Oh, and, uh…" the Doctor pointed back into the room.
The sergeant seemed to understand the Doctor's drift, and quickly responded: "Don't worry, sir, I'll clean up this mess."
"Mess?" questioned the Doctor, with an admonishing tone. "That's not the word I would have chosen, sergeant…" the Doctor checked the soldier's uniform for his name.
"Kiefer, sir."
"Sergeant Kiefer," the Doctor repeated, pointedly pronouncing each syllable with quiet fury.
The Doctor and the sergeant stared at each other icily for a moment, before the Doctor spoke again.
"Those people died. And – oh!" the Doctor pulled at his hair in frustration. "It's moments like this when I hate being so clever." He rounded on the sergeant, his eyes both intimidating and pleading with him. "I can tell from those burns that they died in agony. They were probably still conscious as they were being digested. Doesn't that bother you? It bothers me."
Kiefer's face remained passive, as he listened to the Doctor's vexation.
"It's certainly very tragic, sir. But it is… an occupational hazard."
The Doctor narrowed his eyes, disbelieving of the sergeant's response.
"Occupational…?"
"We are trained to deal with these kinds of events," the sergeant continued.
The Doctor stopped listening to Sergeant Kiefer, and turned his back on him, with a growl of 'soldiers…'
Simmons regarded the Doctor attentively, a little unsure what to make of his reaction.
"Where's this laboratory?" the Doctor asked.
"It's not far," Simmons quickly replied.
"Good," the Doctor grunted, storming off down the corridor.