XI. In a Field of Stone

"Now!"

With an epic cricket bowl, the Doctor hurled the transponder into the shaft.

"Oh, you... you clever thing, you." River wrapped her arms around the Doctor's waist and kissed him hard, while pressing down on the holunit's trigger. The holographic field surrounded herself and the Doctor, effectively erasing them from the scene. The only other evidence of their presence - the transponder - tumbled down the shaft, to the base of the power collector.

The Doctor hesitated at first, but responded gamely to her kiss, wrapping his arms around her waist and pulling her close.

The swarmbots switched trajectory and pursued the transponder. The sentries followed suit, blasting away with their disruptors.

River broke away from the kiss to look down. Hundreds of metres below, bright flashes of light preceded the sound of screaming, tearing metal. The column glowed impossibly bright, leaving an afterimage swimming in her vision. The holounit sputtered and died, leaving them uncloaked.

High above them, the lights at the top of the column sputtered and went dark. The darkness spread, shooting down the shaft, until only a faint glow at the bottom remained.

"Shockwave's coming, let's go!" The Doctor grabbed River's hand and tugged her along the catwalk.

River followed him to the elevator shaft, and they started the long climb up. First came the shuddering boom which shook the building to its foundations. River clung to the ladder, hooking her elbows over the rungs to steady herself. The tremors came, in several long waves, and she imagined fractured rock and splintered metal all over the moon. A deep boom echoed off the walls.

The wave passed, and her very bones were still vibrating. Her knuckles went white and her joints locked, desperate to maintain her hold on the ladder. She slowly worked her hands, and grasped the next rung and pulled herself up. River was thankful the base itself was still standing. Risking their own destruction was certainly a flaw in the Doctor's otherwise brilliant plan. He'd deny it, of course, but when pressed would insist the gamble was precisely calculated. River knew better, but then again, she'd probably have done the same thing.

Panting heavily, they climbed and prised open the lift door on level two - home of the manufacturing plants and materials labs. Which was also where their scans indicated the TARDIS was being held. The corridors had lost their golden glow, illuminated only by pale emergency lights at intervals along the floor. The place was utterly still, and for the first time appeared to be the ancient ruin it was.

The floor was littered with intact but motionless sentries. River leveled her gun at one and toed it, testing. It remained still, the jewel-like lights dull and lifeless.

The Doctor removed the oxygen unit from his face and said, "Deactivated. Although... " he looked around, studying the corridor. "There is some backup power, still."

River shrugged her shoulders, warding off a sudden chill. Was it timesense, or simple human intuition that niggled at the back of her mind? "Something doesn't feel right."

"No, it doesn't. Let's take Fred's temperature, shall we?"

She moved down the corridor, kicking dead sentries aside as she went. She kept her guard up, peering into abandoned rooms. River stopped at a square of phosphorescent light; a terminal inset into the wall. It was still functional, though River thought the term 'functional' was a bit broad in this case. Lines of code scrolled across the screen, interspersed with the occasional pictograph. She thought she recognized the evacuation route from the maps in the crew quarters. She motioned the Doctor over. "Here's something."

The Doctor cracked his knuckles and typed furiously. The terminal was unyielding, and in the end he had to sonic it. "The deadlocks are gone, ah, here we are. Oh."

She raised an eyebrow. "That's a pretty mild 'oh', all things considered."

The Doctor gulped. "Fred, oh, Fred Fred Fred, why did you have to do this? What a remarkable, beautiful, overzealous machine you are." He looked at River, "The generator was destroyed, but Fred's still got battery power. Just enough... just enough for one shot of the gun."

"And he's reached his highest alert level, which means he'll respond as if a large-scale Skarsak attack were on its way."

"Yes. The great big gun has a target. I can't make out the vessel, but it could be anything from an automated container ship or a palace cruise liner."

"Last time this happened, he took out an entire armada - it's probably more than one ship. We can't take the chance it's unmanned. How long do we have?" She looked at him helplessly, knowing deep in her bones that he was going to do something rash. Because he was the Doctor, and he couldn't walk away from someone in danger. Unless it were himself.

"Um," he glanced at his watch, and then back at the terminal. "Forgot to mention, firing the gun will most certainly blow the base. Fifteen minutes, give or take. Not helpful... argh!" He slammed his fist into the wall. "Ouch. Okay, look, we can't just take off, we've got to stop it. Sentries are dead, that makes things easier. Still no oxygen, that's harder... River, we have to give Fred a lobotomy before he can fire the gun. We can use the TARDIS to disable Fred, materialize inside the core and kill him with the feedback."

She put a hand on his arm and forced him to look in her eyes. "Sweetie, I know. It's a good idea. But if we only get one shot at this, we should split up. I can go to the core."

His eyes narrowed and he glared at her. She imagined a thousand different cogs churning away in his brilliant mind, gauging her - their - chances for success. At length he said, "Okay, okay. I'll fetch the TARDIS, and bring her to Fred's core control room. Just - Fred's quantum processors are in a refractorally sealed core, yeah? They're super-cooled. Drain the coolant, just open the plug, and then, if there are vents, open them, too. Just... don't go in. Don't go in, River? Okay? You'll be ... frozen, and overcome by fumes. Not necessarily in that order. If you turn off Fred's air conditioning, it'll buy us some time. Got it?"

"Understood." She gave him a mock salute and smiled softly.

He returned the salute, and reached into the pocket of his shredded environmental suit. "Here, take this," he handed her the sonic. "You'll hardly notice I'm gone." And with that, he turned on his heel and sprinted down the corridor.

"I always notice when you're gone," she murmured to his retreating back.

DAMAGE ASSESSMENT...

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CRITICAL DAMAGE

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CONFIRM SKARSAK ATTACK

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NEW THREAT LEVEL: TAU

MAXIMUM ALERT

OVERRIDE ALL ADMINISTRATIVE CONTROLS

ELIMINATE ALL SAFETY PROTOCOLS

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FINAL OPTION INITIATED

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EVALUATING...

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ENERGY CONVERTER SYSTEM CRITICAL FAILURE

WEAPON FIRE WILL DESTROY FACILITY

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OVERRIDE

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/SECURITY SYSTEM SUBROUTINE COMMAND:

/STAND DOWN

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/MANUFACTURING PLANT SUBROUTINE COMMAND:

/STAND DOWN

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DIVERT ALL POWER TO WEAPONS ARRAY

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/WEAPON ARRAY SUBROUTINE COMMAND:

/FULL POWER INITIALIZED IN 24 KRONTONS

/FIRE AT WILL

River ran to the center of the complex. She met no resistance, probably because Fred's remaining power was focused on its last weapon. She skidded around a corner and past a crew lounge. Emergency lights helpfully guided non-existent Varians to the closest exit points. River reversed their route and followed the lights deeper into the base. The closer she came to the core, the worse the damage was. A crack bisected one wall, exposing sparking electrical wires and oozing insulation.

It was a miniature version of what would be waiting for her at the core. She took two quick puffs of air and moved up two flights of stairs, half bent over in the cramped stairwell. The stairs spilled out into a rotunda. It was the only room in the base that still had full power. A ring enclosed the main room, full of observation decks and control panels. These too, were Varian-sized, and River crouched down and shoved her shoulder into a half-open door. It gave with a mechanical screech.

She scrambled into the room and was faced with a floor-to-ceiling window. Beyond it, Fred's quantum core was suspended in green gel. The Facility Master Unit was a tiered structure, its base attached to the ceiling of the chamber like an upside-down wedding cake. Each tier held an individual quantum processor, and the highest, most advanced functions were housed in the lowest (and smallest) layer, near the floor.

Gazing into the shimmering pool of coolant that protected Fred was like looking at an undersea landscape. River was reminded of her time scuba diving on Antares VII, where the green expanse of ocean held the same mesmerizing stillness. She stepped forward and placed her palm against the glass; she could feel the cold bleed into her skin despite the layers of protection between the observation room and the core.

While Antares was a tropical paradise, Fred lived in a pool of death. The Varian cores - indeed, any quantum core - functioned most efficiently at supercooled temperatures. At a minute fraction above absolute zero, subatomic particles could power the processors, providing the computational power required to bring Fred to life.

Inside the chamber, living flesh would flash-freeze, shatter, and die. Not necessarily in that order. And the green gel, like most coolant, was a cocktail of long-chain organic compounds most certainly toxic to almost every kind of life in the universe.

Time to get to work.

The Doctor ran as fast as his lanky legs would take him. He didn't stop for oxygen, relying on his respiratory bypass system to carry him through.

The bulkhead doors throughout the base had lifted, one of Fred's last attempts to speed the movement of the security assets. Level two was a maze of labs and manufacturing facilities - where hard science met the nuts and bolts of base operations. He passed rooms full of deactivated service bots and stores of replacement parts - mines, structural units, and silenced manufacturing systems. He cut through one of the plants, neatly sidestepping the machinery. It was the size of a cathedral, fully automated, and sporting a three-dimensional printing head that could fabricate individual parts the size of a house. A really, really big house.

Through another junction, another corridor, and he found a smaller-scale fabrication and assembly plant. Sitting lifeless on the finished platform was a full swarm of nanobots - the now-familiar set of buzzbots, sensor bots, skycranes and transmat units.

The Doctor sped past them to the doors of Materials Lab 4, where the TARDIS was being held. Seriously, Fred couldn't be bothered to put the most amazing machine in the universe into Lab 1? The Doctor sniffed at the insult.

The reinforced doors were shut. The Doctor moved to the adjacent control panel. "Oh, dear."

"Skarsak agents and technology will be terminated by the detonation of this facility," said Fred. "Identify means and metrics of imminent Skarsak invasion."

The entire lab was surrounded by a forcefield. Fred was using a precious, final burst of power to utterly prevent the Doctor from reaching the TARDIS. The Doctor tried to access the panel, but it was locked down. Probably using his own stolen subroutine, he thought ruefully. He cast about for a solution. No sonic, no time. River needed him.

"There is no Skarsak invasion, Fred. I tried to tell you before, you're not being logical."

"The behavior of subject designated Doctor is contrary to logic."

"Is it Fred? By what definition of logic? Look, let's play a game." It was worth a try at the very least. The Doctor was usually very good at talking to computers, and couldn't imagine why Fred was such a tough nut to crack.

"Emergency protocols engaged. Recreational subroutines disabled."

"Are you saying you don't have time for fun and games?" The Doctor ran down the hall, trying other doors.

"Recreational activities irrelevant."

"Your builders didn't think so, this place was chock full of entertainment facilities and gourmet restaurants." The Doctor cursed as he ran into a storage cupboard. Everything was a dead end. "Not to mention that great big gun," he said under his breath.

No time... River. His hearts sank as his timesense ticked on. With each passing nanosecond, the possibilities of the next ten minutes narrowed and narrowed, and precious few options were likely to turn out well.

"Look, games are how we learn. It's universal. On the savannahs of Earth, lion cubs stalk and pounce on one another, along with their parents. On that same planet, a family of humans sits around the table playing tiddlywinks. The Varians played games, too." A thought struck him, "Shame you don't have anyone to play with anymore. Ten thousand years, who knows what you might have become if you had someone to talk to."

Fred was silent, processing. "This unit is is purposed with the defense of the Varian Protectorate."

"And it's the last thing you'll do, isn't it? But would the Varians thank you for blowing up thousands of innocents in their name?"

A full minute ticked by. No more time.

"Fred? Fred?"

River found a functioning terminal and sonicked it, calling up the basecode of Fred's support system. It was easy, now that Fred's attention was elsewhere. That wouldn't last for long. Code spilled across the screen, and River spent precious minutes searching for the line of code that would disable the cooling system.

As she worked, the lights around her flickered and dimmed. A deep, soothing voice filled the observation room, speaking Varian. It was not what she'd come to know as Fred's voice, merely a prerecorded message. The exit lights on the floor blinked insistently at her. River squatted next to the terminal. Where was...There! A few keystrokes opened the drains in the rotunda. The green gel drained, revealing the first spiral of Fred's processor.

That must have got Fred's attention. Above her she heard doors boom shut as Fred locked down the core.

Where was the Doctor? He should be here by now. Unless he'd been cut off, or hurt... No. Focus, Dr. Song. A second command opened the vents in rotunda. Warm air rushed in. The evacuation protocol droned on above her head. The doors in the observation room next to hers slammed shut, and River wedged an oxygen canister into hers before it could do the same.

River watched as the coolant level dropped. The third layer, the fourth. It was very nearly done, now. Where was he?

Suddenly, the lights went dead and the consoles shut down. The only illumination was the phosphorescent glow of the coolant as it drained - too slowly - through the floor. The Varian announcer's message changed, and though she couldn't understand the words, River recognized a countdown when she heard one. The entire structure began to vibrate as Fred pulled power from every section to feed the massive gun.

And the Doctor still wasn't there.

FACILITY MASTER UNIT CONTROL CENTER BREACHED

INTRUDER ALERT

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/SECURITY SUBROUTINE COMMAND:

/MUSTER SENTRIES

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/NO POWER AVAILABLE

/ALL SENTRIES DECOMMISSIONED

/ALL SWARMS DECOMMSSIONED

/ALL UNITS DECOMMSISSIONED

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WEAPONS ARRAY PRIORITY

ENERGY BURN NOT AUTHORIZED

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FACILITY MASTER UNIT UNDER ATTACK...

The Doctor paced, despair creeping into his throat. The TARDIS was sealed off. He couldn't run back to the core, he'd never make it in time. And River - River... He ran his hands through his hair and howled in frustration, kicking the bulkhead for good measure.

If he was late, she'd go into the core herself. His beautiful, clever, incandescent River: getting the job done when he couldn't. Like she had at the Library, except now, too soon. The path of their joined future rolled up before him, and winked out.

River took a deep breath and reached out to the TARDIS, trying to sense the Doctor through his connection with the ship. Impressions slipped through her mind like sand. Possibilities stretched out before her; the Doctor was dead, was running toward her. He wore a new face. No... just possibilities, not reality. Focus! He was dead, coolant rising to fill his mouth. And there had never been an Area 52, no Lake Silencio... just a thread that trailed off into the distance.

Her eyes snapped open. No.

He wasn't coming. All right. But she wasn't going to let some overzealous computer rewrite her life.

She checked the coolant levels. There was about an inch of gel left on the floor, she guessed. No matter. River picked up the oxygen canister from the doorway. Hefting it in one arm, she blasted the lock to the quantum chamber and went inside.

He needed something... anything... there wasn't enough time to explore his timesense.

A deep inhalation of oxygen. Maybe the brain cells needed a jump start. His vision began to clear... maybe...

Another hit of oxygen.

What he needed was a rapid way to get to the core. Something Fred couldn't block. Autonomous. With its own power supply. Controlled by simple commands. And... and with its own transmat.

The Doctor ran for the fabrication and assembly room.

FACILITY MASTER UNIT

OVERHEAT WARNING

QUANTUM PROCESSORS -75% EFFICIENCY

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SHUT DOWN SUBROUTINES

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ERROR: IGNORING RETURN VALUE OF 'INT FTRUNCATE(INT,_OFF_T)', DECLARED WITH ATTRIBUTE WARN_UNUSED_RESULT

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CRITICAL FAILURE

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EFFICIENCY -90%

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SYSTEM SHUTDOWN IMMINENT

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EVALUATING...

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SHUTDOWN UNAVOIDABLE

PROBABILITY OF FACILITY MASTER UNIT DESTRUCTION 100%

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/TRANSFER MASTER CONTROL

/WEAPON SYSTEM SUBROUTINE NOW ACTING AS FACILITY MASTER UNIT

/FIRING AT WILL IN 3 KRONTONS

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FACILITY MASTER UNIT...

UNDER ATTACK...

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ERROR

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NON-RECOVERABLE ERROR

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CORRUPTED DOUBLE-LINKED LIST: 0x0000000014cf4ea0

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FILE CORRUPT

ACCESS FAIL...

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LONG LIVE THE VARIAN PROTECTORATE

It was like walking into a solid wall of cold. It chilled River's very bones, eating through the remains of her suit. She shivered violently and slipped on the viscous goop on the floor. Noxious fumes rose up to meet her, burning her nose and throat. She slapped the too-small oxygen mask over her nose and skated her way over to the core. Her feet went numb. She was peripherally aware of the countdown announcement slowing. Heat damage was setting in. Point in her favor.

She started with the processor tier closest to her own height. Up close, she could see the jumper pins on the surface. When her fingers failed to gain purchase, River gave up and fired her disrupter at the connections. The protuberances sizzled and melted in a shower of sparks. One down, only three hundred and some to go. She coughed, and her vision swarm. She took aim at the next plug and fired.

It came with its own controller. Clever Varians.

"Wake up," the Doctor said.

A hundred little robots came to life - buzzbots and sensor bots - flying into a hovering phalanx. The little skycranes grabbed transmat units and placed themselves around the formation, and around the Doctor.

"Transmat me to the Facility Master Unit control room."

River's next shot missed, glancing off the wall and zinging around the room. River ducked. "Dammit!" She swayed and went down on one knee. The coolant soaked through her pants. The sudden chill snapped her eyes open (when had she closed them?). She tried to stand, but her legs refused to support her. "Where-?" She'd lost the little oxygen mask, and that was important. She patted ground around her.

River's vision narrowed to a pinprick of light, and then winked out.