Frost shrugged. "Standard disrupter. I suppose the style's changed a lot in the past ten years. This version is far superior to the old model."

"Really. What's the recharge time?"

"Got it down to three minutes now."

Carrion raised an eyebrow. "Thatis an improvement, but I see you still carry a sword."

"Of course," Frost grinned. "A sword never needs recharging."

"Your attention, please," said Odin suddenly on their comm implants' command channel. "I have discovered something important, Captain. Apparently Commander Starblood had been concerned about possible intruders in the Base even before the alien ship crashed. There are several references in his log to sightings of 'ghosts,' or some kind of presence, by Base personnel. These sightings became so frequent and so disturbing that Commander Starblood ordered six Security Guardians. There's a record of their delivery, two weeks before the alien ship's arrival."

Silence scowled. "Six Guardians? How the h.e.l.l did the aliens get past them?"

"What exactly are Guardians?" said Carrion.

"After your time," said Frost. "They're state-of-the-art Security robots. Fast, powerful, efficient, and a really nasty att.i.tude. They were designed originally for riot control. One per riot. And Starblood ordered six. . . . He must have been really scared. Six would have been enough to stand off a small army."

"And if they're still here, and running loose," said Silence, "we're in real trouble."

CHAPTER SEVEN.

Guardians The marines moved cautiously down the metal stairway, scowling into the gloom below. The guns in their hands swept constantly back and forth, covering every direction an attack could come from. Diana supposed she should find such obvious expertise comforting, but instead it just reminded her of the possible dangers ahead. It almost made her wish she carried a gun of her own. Almost. She was an esper, not a killer. She stuck as close behind the marines as she could without crowding them, holding her lamp high to spread its light as far as possible. Huge shadows moved around them like watching ghosts, but everything else was still and silent.

They'd found the elevator shown on the floor plan, which could have taken them down to the next floor, but none of them had felt like risking it. They had no idea why it was still working when so many other things weren't, and it was only too easy to imagine the elevator breaking down between floors, leaving them trapped in a steel coffin while the air ran out. So they made their way slowly down the stairs, nerves tingling in antic.i.p.ation of an attack that never came.

It was cold in the stairwell, and getting colder. h.o.a.rfrost made patterns on the walls that teased the eyes with hints of meaning. Their breath steamed on the still air, and the heating elements in their uniforms somehow weren't enough to keep the chill out of their bones. Their footsteps rang loudly on the metal steps, and the sound seemed to echo an unnaturally long time in the hush.

Diana knew she should be using her esp to check ahead, but she couldn't bring herself to do that. Not yet. The scan in the lobby had been hard enough, when she'd felt safe and secure. But now that she'd come down into the heart of the darkness, she was afraid to send her mind out for fear it might not come back. She was afraid there was something down there in the dark with them, and she didn't want to risk waking it again. Sometimes she thought it was an alien, and sometimes she thought it might be ghosts of the dead personnel, but all she really knew for sure was that she was scared. So scared that even the awful forms her imagination conjured up were preferable to encountering the real thing again. It was safer to lie to herself and hide in the dark with the marines.

They finally reached the bottom of the staircase, and stood close together at the foot of the steps. To their right, a thick coating of ice almost covered the sign saying level two. The marines and the esper ignored it, their gaze fixed on what the esper's lamplight revealed before them. The corridor walls bulged and seethed with ugly alien growths, and thick strands of shimmering webbing hung down from the ceiling, twisting and turning slowly as though in response to an unfelt breeze. The metal walls had torn and split apart in many places, multicolored wiring hanging out like plastic viscera, as though the alien forms had somehow grown inside the walls and burst out when they grew too large to be contained. Silvery traces ran along the unbroken areas of wall in long, enigmatic patterns, gleaming brightly in the lamplight like metallic veins. They were pulsing slowly with an alien life. The whole ceiling was covered with dark, wartlike nodes the size of a man's head, surrounded and connected by swirling chalky-white spirals. And thick on the air, was a harsh sweet smell like a disturbed grave.

"What the h.e.l.l is this?" breathed Stasiak, swinging his gun back and forth, unable to settle on a single target. "The place looks . . . diseased."

"Infested, anyway," said Ripper. "I think we can be sure now that the aliens came here after they left their ship." He glanced at the esper beside him. "This . . . mixture of living and unliving-is this the same kind of thing you found on the alien ship?"

The esper had to swallow hard before she could answer, but when she finally spoke her voice was cool and quite professional. "The same kind of thing, yes. Only the ship was dead, or dying. This looks alive, and functioning. The alien crew must have brought it with them, as some kind of seed, perhaps. But why?

Surely they didn't bring about changes as extensive as this just so that they could feel at home? There must be a purpose to it."

"If there is, it's an alien purpose," said Ripper. "Something we might not even recognise, let alone understand. I think we need the Investigator down here to check this out, before we go any further."

"Wait a minute," said Stasiak quickly. "Let's think about this first. We don't need to know what this stuff is. It looks weird and smells worse, but it's not exactly aggressive, is it? We're supposed to be looking for the Base personnel, and we don't need Frost for that. We're marines; we can handle this without an Investigator to hold our hands."

Ripper looked at Stasiak thoughtfully. "This isn't like you, Lew. It's an improvement, but it isn't like you.

What are you up to?"

Stasiak grinned. "Odin's recording everything that happens here, remember? And you can bet a lot of higher-ups are going to be studying this record. This is our chance to look good in front of people who matter, and do ourselves a bit of good in the process. Why let Frost steal all the glory? There's money and fame in this; I can smell it."

"People have died here," said Diana sharply. "And all you can think of is how best to turn it to your own advantage?"

Stasiak shrugged. "If they're already dead, there's not much left I can do for them. So we might as well help ourselves, while we can."

"And if whatever killed these people finds us?"

"Then we avenge the dead," said Ripper. "We know our duty, Diana. We're marines."

Diana sniffed and looked away, ostensibly studying the alien scene before her. Ripper shrugged. "Odin, are you getting all this?"

"I see everything you see," murmured the AI in his ear. "It's really most fascinating. Please proceed further into the changed area. I need more information on the extent of the changes."

"Wait a minute," Stasiak interrupted. "There's no point in rushing on blindly. There could be all kinds of unpleasantness up ahead."

Ripper looked at him, amused. "A minute ago you were all for plunging into the thick of it, in search of glory."

"I'm ambitious, not crazy. Let's handle this nice and easy, one step at a time. The only good hero is the kind who survives to talk about merchandising."

And then he broke off, and they all looked round sharply as a single, echoing thud came out of the darkness ahead of them. It was heavy and threatening, and sounded quite deliberate, as though whatever was responsible for the sound had wanted it to be heard. Ripper and Stasiak levelled their disrupters on the corridor ahead. Diana's right hand went to the force shield bracelet on her left wrist, but she hesitated to activate it. The energy crystal that powered it had a limited life span, and she didn't want to use it up unnecessarily.

"Odin, can your sensors detect anything alive on this floor?" said Ripper softly.

"I'm afraid my sensors are currently unable to penetrate the Base," the AI replied. "Something is blocking them. My only sources of information are what I see and hear through your comm implants."

More noises came out of the darkness, a slow, regular thudding like the beating of a giant heart. The floor vibrated beneath their feet in time to the rhythm, and something large and hulking came out of the gloom towards them. It was huge, filling the corridor, and Diana shrank back, a child again, frightened by the bogeyman in the dark. The figure stopped suddenly a dozen feet away, its blue steel exterior glinting in the wavering lamplight. Its bent head sc.r.a.ped against the ceiling, and its metal hands were studded with razors. Stasiak swore softly, but his hand was steady as he turned his disrupter on the metal figure.

Captain Silence's voice rang suddenly in their ears. "Listen up, people. We have a problem. Odin has just told me there are Security Guardians somewhere in the Base. Don't engage them, under any circ.u.mstances. It's very possible they've been programmed to protect this Base against intruders. If you see one, retreat immediately."

"Thanks for the warning," said Ripper, "but it's just a bit late. We're looking at one right now. Please advise."

"Get the h.e.l.l out of there," said Silence immediately. "Make no threatening moves and back away. If it starts towards you, run. There are probably more on the way. They're crawling with weaponry and they don't take prisoners. As long as you keep a fair distance away, you should be safe."

"Should?" said Stasiak. "What do you mean, should? I'm not moving a muscle until I'm sure it's safe."

"Shut up, Lew," said Ripper. "Esper, back away and start up the stairs. We'll follow you."

"All right," said Diana quietly. "I'm starting now."

She stepped back cautiously, and the huge metal figure raised a hand to point at her. A disrupter beam flew from a finger and blew apart the metal stairway in a rain of jagged shrapnel.

Cries and screams and obscenities burst from Silence's comm implant, drowned out almost immediately by the sound of an explosion from below. The noise was deafening, and the floor shook briefly. Carrion and Frost looked to Silence for orders.

"Whatever's happening down there, there's nothing we can do," he said flatly. "By the time we could get there it would all be over, one way or another. And the last thing we want to do is provide a Guardian with new targets. Esper, marines, can you hear me? Fall back. I repeat, fall back." He waited, but there was no reply, only the quiet hum of an open comm channel. "Odin, access what they're seeing and patch me in."

"I'm sorry, Captain," said the AI steadily. "Something inside the Base is interfering with the comm network. I have lost all visual contact with the esper and the marines. I am still monitoring audio signals, but I can't be sure how long that will last. I strongly advise that you leave Base Thirteen now. You are not equipped to deal with Guardians."

"Want to bet?" drawled Frost. "Point me at one. Anything that gets in my way is going to regret it."

Carrion looked at Silence. "Is she always this confident?"

"Yes," said Silence. "Frightening, isn't it?"

Carrion looked away suddenly. "Captain . . . something's coming, and it's very close."

Frost and Silence drew their guns and covered the two approaches. The wide corridor was still and open, with doors leading off at both sides. The only light came from the lamp Silence was holding, a pale illumination just strong enough to show both ends of the corridor. Nothing moved, but the shadows had edges. What had been just another corridor was suddenly openly menacing, every doorway a threat.

Silence and Frost moved to stand back to back.

Carrion leaned on his staff, frowning, as though listening to something audible only to him. Silence strained his ears against the hush, but couldn't hear anything.

"What is it?" he said quietly to the outlaw. "Which direction is it coming from?"

Carrion's eyes closed. "They're here, Captain. They're here."

The wall to their right tore apart like paper as the Guardian burst through into the corridor. Thick strands of colored wiring fouled one arm, but the Guardian snapped them with one easy movement. The machine was eight feet tall, a broad metal colossus with glowing eyes and a constant, unnerving grin on its blue steel face. Razor blades protruded from its arms and legs, and the knuckles on its hands were spiked. It was not alive, but hate and violence were a part of its nature. It was a killing machine, fashioned in the shape of a man because it was more frightening that way.

"Big, isn't it?" said Carrion.

The sound of heavy metal footsteps rang out at both ends of the corridor, and two more Guardians appeared, blocking off the only means of escape. The three machines stood unnaturally still, studying their targets, and then they surged forward, too fast for the human eye to follow. Silence aimed and fired his disrupter at the nearest Guardian as it emerged from the wreckage of the wall. Its force shield snapped on just in time to deflect the energy bolt, and then disappeared. The machine raised a hand and pointed, and Silence threw himself to one side as an energy beam blew a hole in the wall where he'd been standing. Silence hit the floor rolling, and was quickly back on his feet again. He slapped the metal bracelet on his left wrist, and a force shield sprang into being on his arm. A yard-long oblong of glowing energy, it was capable of deflecting any energy weapon. For as long as it lasted. The Guardian could turn its own shield on and off with split-second timing, so that its shield lasted practically forever. Silence didn't have that option. He also had another three minutes to wait before he could use his gun again, and the Guardian was right on top of him.

Silence kicked open the door to his left, darted into the room and slammed the door shut behind him. He didn't really think the door was going to stop something that could crash through walls, but hopefully it would buy him a little time while he worked on what the h.e.l.l to do next. A metal fist punched a hole in the door. Silence watched, fascinated, as an arm followed the hand through the hole, and then the Guardian pulled it back sharply, yanking the door out of its frame. The Guardian stepped unhurriedly into the room, widening the doorway as it did so. Silence backed away, holding his shield up before him.

The corridor was plunged into darkness as Silence disappeared into the side room, taking the only lamp with him. Frost cursed dispa.s.sionately and switched to her infrared implants, only to discover the Guardians were shielded against displaying any heat signs. Frost immediately switched to ambient light and activated her force shield. The shield's glow was more than enough to show her the Guardian advancing on her. Frost fired her gun, but the energy bolt glanced harmlessly off the machine's force shield. Frost shrugged calmly, put her gun away, and drew a knife from inside her boot. It was viciously wide and almost a foot long, and its edges looked blurred and uncertain.

"Monofilament edge," said Frost to Carrion. "Cut through anything. Have to be careful with it, though, or it'll have your fingers off."

"Those things were illegal in my day," observed Carrion.

"They still are. But I won't tell anyone if you won't."

And then the Guardians were upon them, and there was no more time for talk. Frost threw herself forward, and the knife lashed out to cut a chunk off the Guardian's hand. Its built-in disrupters all fired at once, but her force shield protected her. Frost brought the energy field across sideways, and its razor-sharp edge sliced clean through the Guardian's other hand as it reached for her. The huge metal arms swept suddenly in, intending to grab the Investigator and crush her against the blades on its chest.

Frost dropped to her knees and rolled to one side, and the great arms closed on nothing. Frost jumped back, scrambling quickly to regain her feet, and the Guardian went after her, reaching for her with its crippled hands.

Frost darted in and out, slashing at the Guardian with her knife, cutting and carving it, but unable to do any real damage. It was just too big, and her knife was too small. The machine's computer-enhanced moves were inhumanly fast, and only her Investigator's .training enabled her to avoid it. And she knew she couldn't maintain that kind of speed for long. She could turn and run. The Guardian didn't look as if it were built for high-speed pursuit. But that would mean abandoning Carrion and the Captain, and her duty. Investigators didn't run. She darted in under the Guardian's reach, jammed her gun against its chest, and pressed the stud. Nothing happened. There hadn't been enough time for the energy crystal to recharge. She scrambled up the Guardian, climbing it like a cat, carefully avoiding the blades on its chest, and dropped to the ground behind it. She spun round quickly, and stabbed the machine in the back before it could turn. It shuddered once, but that was all. The blade wasn't long enough to reach the parts that mattered. She yanked the blade out, and a metal arm whirled round and sent her flying down the corridor. She'd got her force shield up in time, but the impact was still enough to knock the breath out of her. She got her feet under her and backed away as the Guardian advanced on her, implacable and unstoppable as death itself.

Carrion crouched down, and froze where he was when Silence disappeared with the lamp. In the dark, the Guardian could only track him by sound. Unless the d.a.m.n thing had infrared too. And then Frost turned on her force shield, and Carrion's long-neglected eye-enhancements kicked in, boosting the ambient light. Carrion straightened up as he saw the third Guardian advancing on him. He drew his power about him, crackling and sparkling on the air, and reached out to tear the machine apart. And his power dropped away and was gone in an instant. Carrion stood for a moment, staring blankly, and that was almost enough to get him killed. The Guardian raised its hand, and all the disrupters in the hand fired at once. Carrion threw himself to one side at the last moment, old combat reflexes coming to his rescue.

The d.a.m.n thing had psi inhibitors built into it. They worked on the opposite principle to his power lance, damping down psi energy instead of augmenting it. The Empire used them to keep espers in line. They reacted to build-ups in psionic energy and cut in automatically once it rose above a certain level. Carrion backed away from the Guardian, holding his useless power lance out before him.

The Guardian loomed over him, reaching for him with razored hands. Carrion reached inside himself and drew on his power. The psi inhibitors prevented him from doing anything dramatic, but it was surprising what you could do with even small amounts. He reached out with his mind, a whisper of psychokinesis almost too small to register, and slipped it deftly between the Guardian's feet and the floor. All friction vanished in a moment as he concentrated, and the Guardian's feet shot out from under it. It fell on its back with a deafening crash, and Carrion reached quickly out to do the same to the machine threatening Frost. It hit the floor hard, and Frost stepped forward and drove her monofilament knife into its gleaming skull. The Guardian jerked and trembled, and lay twitching on its back on the floor. Frost pulled the knife out and calmly set about sawing the grinning head off.

The wall to Carrion's left exploded, throwing shrapnel across the corridor, and Carrion had to put up his esper screen to protect himself. He couldn't concentrate on that and the Guardian, and the machine rose quickly to its feet again. Silence clambered through the hole in the wall. A metal hand reached out after him, and Silence threw himself forward to avoid it. He scrambled away and was quickly on his feet again, standing beside Carrion and breathing hard. The Guardian before them fired a disrupter, and Silence blocked it with his force shield, holding it at an angle so that the beam glanced off and struck the Guardian that was climbing through the hole in the wall. It stopped the beam with a force shield, but was slowed for a moment. Silence grinned breathlessly.

"Same trick I used to make that thing provide me with an exit through the wall."

"Very clever," said Carrion. "Almost as clever as disappearing into another room and taking the only light with you."

"Ah," said Silence. "Sorry about that. It's been a while since I did any hand-to-hand stuff. I'm rather out of practice."

They jumped in different directions as Carrion's Guardian fired again, and the vivid energy beam flashed past them down the corridor to blow a hole in the far wall. Silence's Guardian crashed out into the corridor again, shaking off enc.u.mbering debris, and turned to face Frost. She hefted the severed metal head in her hand and threw it at the Guardian. The machine caught the head easily, put it down on the floor with surprising gentleness, and started toward the Investigator. She grinned at it unpleasantly, her knife held out before her. And then the headless machine on the floor behind her reached out with a partly severed hand and grabbed her firmly by the ankle.

Carrion raised his esp as high as he dared, focused his psychokinesis tightly, and punched a hole right through the chest of the Guardian before him. It shuddered under the impact, but did not fall. The outlaw retreated. Silence at his side.

"Is there any way of beating these things?" said Carrion.

"Not really, no," said Silence. "I'm amazed we lasted this long. They're supposed to be unstoppable. But then, that's never bothered you before."

And then the Guardian was upon them, and there was no more time for words.

Diana crouched down behind her force shield, trembling violently as three Guardians advanced on her.

The two marines had already fired their disrupters, to no effect, and they too were reduced to hiding behind their force shields and looking frantically around for a way out. The Guardians strode unwaveringly through the alien-infested corridor, ignoring everything except their targets. Ripper pulled a grenade from his belt, primed it, and tossed it into the midst of the three machines. It blew a second later, and the corridor filled with alien fragments and thick, choking smoke. Stasiak grabbed Diana's wrist and hauled her after him as he and Ripper ran down a side corridor, away from the smoke and the three undamaged Guardians, already striding through the smoke after them.

The alien changes became stranger and more overpowering as they fled deeper into Level Two, but Diana was too busy coughing the smoke out of her lungs to pay much attention to her surroundings.

Tears were streaming down her face, as much from shock as the smoke. She'd never seen anything so deadly efficient as the Guardians. They scared her on some basic, primal level that left no room in her for anything but flight. The Guardians were everything about the Empire that had ever threatened or punished her-brute symbols of authority, relentless as justice or revenge. She could no more have raised a hand against them than she could have defied her own conditioning.

The marines' pace slowed as they left the smoke behind them, but they could still hear the sounds of the Guardians' implacable progress not far behind them. Stasiak produced a small capsule from somewhere and swallowed it dry, grimacing at the effort. He offered one to Ripper, who got his down more easily.

Stasiak grinned at Diana, his eyes already bright and gla.s.sy.

"Just a little something, to give a fighting man an edge. You want one?" Diana shook her head. She didn't trust battle drugs. Stasiak shrugged and pulled her on. "It's your choice. But don't slow us down, or I'll have to leave you. Right, Rip?"

Ripper nodded brusquely, without looking round, and Diana fought to keep up with the marines as they made their way down a corridor distorted by strange alien growths. The hanging streamers of webbing grew steadily thicker, clinging stickily to the marines and the esper as they pushed through them. The corridor grew narrower, pressing in uncomfortably from all sides as the alien growths ran wild. It seemed to Diana that they'd left the Base behind and were running through a harsh new alien world. But the Guardians were still following. She could hear them. The changing alien nature of their surroundings didn't seem to be slowing the machines at all. And then a side corridor ended in a great swollen ma.s.s of alien tissue, bringing the three humans to a halt. The marines cut at the spongy ma.s.s with their swords, but it simply absorbed their blows without effect. They turned and glared back down the corridor. Stasiak swallowed another capsule. The sound of approaching metal footsteps came clearly on the quiet.

Ripper tapped Stasiak on the arm and gestured at the ceiling. Stasiak looked puzzled, but then his face cleared as Ripper hefted his gun. They aimed their disrupters at the ceiling, at the point where the Guardians would enter the side corridor. Diana stood behind them, her force shield humming loudly, and tried to control her trembling. And then the Guardians appeared at the end of the corridor, and Stasiak and Ripper fired at the ceiling above them.

The alien growths exploded and the ceiling blew apart. Fat sparks flew on the air as electrical systems fused and failed and half the floor above collapsed onto the Guardians, burying them under tons of rubble. The marines and the esper watched in silence as the wreckage slowly settled, and then Diana surprised herself with a loud whoop of glee. The marines laughed and whooped a few times themselves.

They all turned off their force shields and hugged each other, giddy with relief. And then they fell silent as the wreckage shifted. Broken metal and ragged alien tissues stirred and fell back as a Guardian rose slowly from the debris. Its blue steel exterior was barely scratched.

The Guardian advanced unhurriedly on Silence and Carrion. It knew there was nowhere they could go.

If they tried to run it would shoot them, and if they stood their ground and tried to hide behind their force shields, it would tear them apart. At the other end of the corridor the Guardian Frost had beheaded was clinging firmly to her ankle, while the third Guardian advanced on her. Silence looked desperately at Carrion.

"Do something! Use your lance!"

"If I try the same trick again, the psi inhibitors will stop me," said Carrion calmly. "If I persist, they'll burn my brain out."

Silence backed slowly away from the Guardian, and Carrion moved back with him. The Guardian lifted its hands to cover them with its disrupters. Silence thought furiously. The d.a.m.n things had to have a weakness somewhere. Everything had a weakness. Except the Guardians had been designed to be unstoppable. Inhumanly strong, computer-fast reflexes . . . computers. Silence seized on that thought.

The Guardians were part of the Base's Security systems, which meant they were run by the Security computers. . . .