And then the alien appeared at the end of the corridor, and Frost stopped talking. It was big, filling the corridor from wall to wall and from floor to ceiling, like a slug in its tunnel. The dark, ribbed body looked long and powerful, with thick cables of muscle standing out and pulsing like veins. Metallic strands were threaded through its flesh-not added, but a living part of its body. Long, bony limbs protruded at regular intervals along its bulk, poling it along the walls. Sharp metal barbs and spikes thrust up from its glistening back, and its end was too far away to be seen. The blunt head had no eyes, or any other obvious features except for metallic teeth that snapped shut again and again in its wide maw, like the closing of a man-trap. The mouth was big enough to take a human head as a morsel, and the teeth shone like daggers. It surged forward, foot by foot, huge and threatening like a thundercloud come down to earth.

Its limbs rattled against the metal walls, and its breath hissed in the vast mouth.

Diana wanted to look away, but couldn't. The thing offended her on some deep, primal level. It was a mixture of living and unliving, life and technology but grown, not made. Things that should never have known sentience or animation were an intrinsic part of its being. She tried to imagine what kind of h.e.l.lish pressures or evolution could produce such a creature, and couldn't. It was too alien, too different. The creature blazed in her mind, the strength of its presence blasting aside her shields till she stood naked and helpless before it. The alien looked at her with its eyeless head and knew where she was, and the shape and texture of its thoughts were made clear to her. They made no sense to her, no sense at all.

"It's bigger than I thought," said Frost casually. "It must have grown considerably since it left its ship, presumably from feeding on the Base personnel. I wonder how big it would grow eventually, without restraint. . . . Still, that's a problem for those that come after us. Stand back, esper. I'm going to blow a hole right through it."

"Your gun won't stop it," said Diana. "Nothing can stop it. It's too big. Too different."

"h.e.l.l," said Frost. "It's just an alien."

She raised her disrupter, trained it on the alien's blunt head, and pressed the stud. The searing energy bolt burned a hole through the head, and oily black blood spattered across the walls and ceiling. The alien howled deafeningly, the sound reverberating through Diana's bones as well as her ears. The great head swayed back and forth, and Frost looked on dumbly as the ruptured flesh knitted itself together, steel and silver traces scabbing over the gaping wound like metal sutures. Frost put away her gun.

"I think we're in trouble, esper. I was rather counting on the disrupter to take care of the alien. Still, when a plan fails, improvise. I've got a few grenades left. When I say the word, you run. And don't hang about, because I'm going to be right behind you."

She pulled a grenade from her bandolier, hefted it casually, and then primed it and rolled it along the floor towards the alien. She yelled to Diana to run, and the esper turned and fled down the corridor. The alien lunged forward, its bulk smothering the grenade. Frost turned and ran, quickly catching up with the esper. Frost hurried her on with harsh words, and then saved her breath for running. The grenade went off, and the floor shuddered under their feet. Frost allowed herself a moment of satisfaction, and then the alien's roar filled the corridor, harsh and unrelenting. The floor trembled again, this time from the alien's ma.s.sive weight as it bore down on them, in pursuit. Frost tried to visualize how fast something that big could move, but had to abandon the attempt. Nothing in her training or experience had prepared her for this alien. It was too different, too unlike anything humanity had ever encountered before.

She accessed the floor plan, and led Diana into the smaller, narrower corridors hoping they'd prove too small for the alien's bulk. But everywhere they went, the alien had been there first. Strange growths erupted from the sweating steel walls, and shimmering strands hung down from the torn ceiling. And finally they had to stop for Diana to get her breath. Frost looked impatiently around her while the esper leaned on her arm for support, head hanging down as she fought for air. The Investigator was still breathing slow and easy. Her training had prepared her for worse than this. She could have escaped the alien easily if it hadn't been for Diana, but she couldn't bring herself to abandon the esper. As long as the bait was still held dangling before the alien, it should concentrate on the esper and not concern itself with what Carrion and the Captain were doing.

She glared back down the corridor into the impenetrable gloom, gun in one hand, incendiary grenade in the other. She might not be able to kill the alien, but she could sure as h.e.l.l hold its attention. She looked unhurriedly about her, sizing the corridor up for possible ambushes and fast exits. There were holes everywhere, in the walls and in the ceiling, some of them leading into tunnels seemingly big enough to swallow theDarkwind' s pinnace. The alien had been busy.

Frost frowned suddenly as she realised the trembling in the floor had stopped. The alien must have decided on another route, a roundabout way to take its prey by surprise. Which meant any of the holes might become an opening for the alien's attack. She approached the nearest of the larger holes and peered cautiously into it. Deep in the darkness she heard a faint muttering, a familiar cacophony of human and alien sounds. She primed the incendiary grenade, counted three quickly, and threw the grenade as far down the tunnel as she could. Then, stepping to one side, she flattened herself against the corridor wall.

There was a dull roar, and smoke and flames billowed out of the hole, along with flying fragments of alien tissue. Frost grinned savagely, and then trotted down the corridor with Diana in tow, pausing to scorch each of the larger holes with a blast from her disrupter. The vivid energy bolts lit up each tunnel as she fired, but there was never a trace of the alien, and the gun took a little longer each time to recharge between shots.

Frost stopped near the end of the corridor, and peered uncertainly about her. She was doing a lot of damage to the Base, but she was no nearer stopping the alien. It should have found them by now. She wasn't foolish enough to think they'd lost it, or left it behind, which meant it had to be planning something in its devious, inhuman mind. Frost smiled. In her own quiet way she was enjoying the chase. It was the first real challenge of her abilities she'd ever had, the first opportunity to try and outthink something that didn't think the way humanity did. She had the upper hand. As long as she and the bait kept moving, the alien was helpless to do anything but chase her. It was too large, too heavy, and too stupid to do anything but follow where she led. And when the Captain and the outlaw had destroyed the heart of its web, she'd turn on the alien and have it run for a while, while she pursued. She snapped her head round suddenly as she caught a faint whisper of the alien's muttering again. She looked at the esper, who was standing with her eyes closed, trembling violently.

"It's here," said Diana. "It's found us."

"Where is it?" said Frost. "I can't see it anywhere."

"Close," said Diana. "Close."

Frost looked quickly back and forth, straining her ears for any more of the alien muttering, but nothing moved in the corridor gloom, and the air was still and silent. Frost frowned, and tapped her gun against her thigh. Wherever it was, she should still get plenty of warning of its approach. The alien couldn't get anywhere near them without the floor trembling under her feet to alert her. Even if it came through one of the tunnels in the walls. And then something made her look up.

The alien's blunt head emerged from a vast hole in the ceiling like a maggot in a rotten apple. Frost grabbed Diana and hurled them both frantically to one side as the monster dropped out of the ceiling. The floor shuddered as it hit. Frost hit the floor rolling and was quickly back on her feet again, a grenade in her hand. She primed it, rolled it down the corridor towards the alien, hauled Diana to her feet, and all but threw her round the nearest corner. She counted quickly under her breath as they ran down the side corridor, and then a blast of superheated air blew past the corridor entrance, followed by the alien's roar.

Frost grinned. She might not be able to kill the d.a.m.n thing, but she could still hurt it.

She pushed the esper ahead of her as they ran, and took the opportunity to examine her disrupter. The energy crystal was seriously depleted, good for only three or four shots at most. The floor was trembling under her feet again. The alien had to be close behind them. She risked a look back, and swore dispa.s.sionately. It was closer than she'd expected, and gaining on them. The thing could move surprisingly fast for its bulk. Frost smiled briefly. She'd always been the pursuer, never the pursued. This was a new experience for her. She found it exhilarating.

They rounded the next corner and then skidded to a halt as they found a dead end. What had been an open pa.s.sage on the floor plan was now sealed off with a thick ma.s.s of alien webbing. Frost hefted her disrupter. The gun still had enough energy blast a way through, but she might need that power to fire at the alien. She shrugged, and levelled the gun at the webbing. The vivid energy bolt tore through the web, blackening the edges of the ruptured webbing. Frost started forward, only to stop as the web slowly re-formed, knitting itself together with effortless skill. The way was blocked again, and she'd wasted one shot. She didn't see any point in wasting another. She looked quickly about her. Here too there were holes in the walls and ceiling, and no way to tell where any of them led. More of the alien's work. Frost turned to the esper, who was looking back the way they'd come with wide eyes and trembling mouth.

"We're going to have to make a stand, esper. Or rather, I am. You can't help me, and you might get hurt if you get in the way, so I want you to go on alone. Pick one of the tunnels. They have to lead somewhere. Choose one of the smaller ones and the alien won't be able to follow you. I have to stay here and hold its attention until the Captain and Carrion have finished their business."

"You can't face that thing on your own," said Diana. "The gun didn't hurt it, and the grenades only slowed it down. If you stay here you'll be killed. Come with me. I'll make us both invisible, and we'll lose the alien in the tunnels."

"No, esper. We have a job to do, remember? We have to keep the alien occupied."

"You can't do that if you get yourself killed. Stay here and you'll die!"

Frost raised an eyebrow. "It's not that certain. I am an Investigator, after all. We can't both go into the tunnels. They're unknown territory to us. Certainly the alien has to know their layout a d.a.m.n sight better than us. You go on, esper. I'll hold it here. You have to survive, to be the bait again, if necessary. And if you're going to lead the alien a chase without me, you're going to need a good head start. Go on, esper."

Diana looked at her steadily. "You're going to die here, aren't you?"

"Not if I can help it."

"Aren't you?"

Frost signed resignedly. "Yes, esper. Quite probably. But that doesn't matter. I know my duty. I always knew I'd die in the field and not in my bed. Comes with the job. I don't mind. It's my duty and it's my life.

It's all I've ever wanted."

"You mean it's what the Empire made you want. They programmed you, just like they did me. They ruined your life and made you love it, and now you'll die for them, because your conditioning won't let you do the sensible thing and run."

"No, Diana, that's not it. I'm going to stand and fight because that's what I do best. We're buying time for the others, me by fighting, you by running. Now do as you're told and get into that tunnel. Please."

Diana stepped forward suddenly, and hugged Frost tightly. The Investigator just stood there for a moment, and then gently hugged her back. Diana let go, and Frost helped her climb into the nearest tunnel mouth. Diana smiled back at Frost, her lips pressed tightly together so they wouldn't tremble and spoil the moment, and then she turned and disappeared into the tunnel, taking her lamp with her. Frost adjusted her eyes to make the most of the ambient light, and turned back to face the corridor. Her force shield hummed briskly on her arm, and her sword was a comforting weight in her hand. She breathed slowly, coolly, and her hands were perfectly steady. What the h.e.l.l. It was only an alien. Something moved in the shadows at the end of the corridor, and Frost smiled widely.

At the heart of the alien web, Carrion and Captain Silence looked at each other speechlessly as the AI told them of the nuclear countdown in a calm, conversational voice. Silence slammed his gun back into his holster.

"Well, that's great. Just great! Now what the h.e.l.l are we going to do?"

"If I might suggest, Captain," said Carrion, "this is something we might do better to discuss on the run.

We have less than thirty-two minutes to locate the esper and the Investigator, evade the alien, get the h.e.l.l out of Base Thirteen, persuade your computer to let us back on the pinnace, and get off-planet before the nuke blows.

"In other words," said Silence, "we're going to die. What the h.e.l.l, we might as well give it a try, just to be contrary. Odin, work out where we are and show us the quickest route out of here."

"I'm afraid I can't do that," said the AI. "Firstly, I will not let you back on board the pinnace. You are still quite probably contaminated by the alien. Secondly, the Empire is going to need the alien's body, and as much of its technology as possible, to examine. Given the potential threat of this new species, the Empire will need all possible information as to the extent of that threat. I must insist you do all in your power to preserve the Base and its contents. I regret the necessity for such harsh measures, Captain. My programming requires that I do this. You know how it is."

"Just when you think things couldn't possibly get any worse, they do," said Silence. "I'll make you a deal, Odin. You agree to get us off-planet and safely back to Quarantine on theDarkwind , and we'll save the Base and its contents from destruction. What do you say?"

"Agreed," said the AI. "My programming allows me to be flexible during emergencies."

"Right," said Silence. "That's a start, anyway."

"Pardon me," said Carrion, "but just how are you planning to defeat the alien and defuse the nuke in under thirty-one minutes?"

"Beats the h.e.l.l out of me. Odin, you must have forged some links with the Base computers by now.

Can't you patch into the systems running the countdown, and turn it off?"

"Not at present, Captain. Since this was intended as a last-ditch self-destruct option, the Empire built in a great many safeguards to ensure that the countdown could not be interfered with, once initiated. The alien managed to suspend the countdown in some manner, but I confess I am at a loss to explain how. I am doing my best to access the relevant systems, but my best-guess a.n.a.lysis suggests that will take me significantly longer than the thirty-one minutes remaining on the countdown."

"Didn't you just know he was going to say that?" Silence said to Carrion. "Do you have any ideas?"

"Do we know where the bomb itself is located?" said Carrion, frowning thoughtfully.

"Well, computer?"

"The exact location is protected by Security codes I do not have access to. Logic suggests it is concealed somewhere on Level Three, to ensure maximum destruction."

"Whatever we're going to do, we'd better do it quickly," said Carrion. "And we have to contact Frost and Diana. They may be facing the alien by now, and they still think they have all the time in the world to deal with it."

"There is a way," said Silence slowly. "After all, this doesn't affect just us. We're not alone on this planet, are we. Carrion? There's always the Ashrai."

The alien came boiling down the corridor towards Frost like a flash flood, impossibly huge, impossibly fast. Its mouth gaped wide, revealing its razor-sharp teeth. It was on the Investigator in a second, and she launched herself forward, vaulting over the alien's lowered head and onto its spiked metal back. She landed awkwardly, trying to dodge the spikes and the barbs, but quickly regained her balance. She swept her force shield round in a circle, the sputtering edge shearing through the spikes, and then, having made herself some room, she slammed her sword down into the alien's head. The blade sank half its length into the leathery flesh, and the alien howled shrilly. It smashed its head against the corridor wall, trying to shake off the pain it felt, but Frost held onto the sword with both hands, and kept her balance.

Thick black blood pooled around her feet, and Frost grinned savagely as she stirred the sword around in the alien's head, searching for the brain. The alien screamed, the vast sound hammering through Frost's head, and its long body convulsed as it struggled to throw her off. Frost used all her strength and forced the sword in another few inches. She worked the blade from side to side, trying to widen the wound, but even as the dark flesh split apart, metal traceries sprang out of the raw meat to repair the wound. The flesh healed incredibly quickly, and the metal sutures were strong enough to resist her sword's edge. And slowly, inch by inch, the sword was being forced back up and out of the wound it had made.

Frost lifted the force shield on her arm and brought it down like a hammer. The edge of the energy field pa.s.sed through the leathery flesh like mist, leaving a long rent behind it. She knelt down beside her sword, and the force field spat and sparkled as she buried it in the alien's back. The alien threw itself back and forth, its wailing voice painfully loud as its cries echoed and re-echoed from the corridor walls.

Frost fought to keep her balance as the alien whipped its head from side to side. Metal spikes thrust up around her, and her shield jerked out of the alien's back. Frost leaned on her sword with all her strength, but still the blade was forced up and out of the alien flesh.

And then a pit opened up in the alien's back beneath Frost's feet, and sucked her down. She was knee-deep in the alien before she could even react, hidden muscles crushing her legs. She snarled at the pain and cut desperately about her with her sword and her force shield, but still the alien flesh sucked her down. It closed around her like a living sea, absorbing her struggles and repairing its wounds as fast as Frost could make them. She groped for the monofilament knife in its sheath on her leg, but it had already disappeared into the alien's body. Something dragged at her feet, pulling her down till she was waist-deep in the alien. The dark flesh rose up like a tidal wave and swept towards her.

Diana looked down from the mouth of a tunnel high up on the wall, and clenched her fists helplessly as she watched the Investigator disappearing into the alien's back. She knew she should be using the time Frost was buying her to get away, but she couldn't just turn her back and let the Investigator die. She couldn't just leave her. A cold hand clutched at her heart as the tidal wave rose up and rolled unstoppably forward. Unless she did something, and quickly, Frost was going to die. But what could she do? She was an esper, not a fighter. Never a fighter. She looked wildly about her for inspiration, and her gaze stumbled across a ma.s.sive, blocky wall-unit not far from the tunnel mouth.

She didn't stop to think about what she was going to do; because she knew that if she did, she probably wouldn't do it. First, she had to get the alien's attention. She dropped her mental shields and cast aside her invisibility like a veil she no longer needed. The great alien head swung round immediately, staring up at her blindly but knowingly. It wanted her, and now it knew where she was. Frost was still sinking into its back, but more slowly now, as though the alien wasn't concentrating on her anymore. It had her, but it wanted the esper. The huge body surged forward, its stumpy legs poling it along the steel walls, leaving dents in its wake. Diana slapped her force shield bracelet, and it sprang into being on her left arm. The alien lifted its head high, searching for her. Diana leaned out from the tunnel mouth, hanging precariously by one hand, and sliced at the wall unit with the edge of her shield. The shimmering energy sliced through the unit's supports, and it lurched drunkenly away from the wall, held only by a single cable. Diana leaned out further, most of her weight hanging out over the drop. The alien's head reached for her, only inches away. Diana gritted her teeth, stretched out her arm, and sliced through the remaining cable. The unit tore itself away from the wall and crashed down onto the alien's head, its ma.s.sive weight hammering the creature's head to the floor.

Diana dropped down onto the alien's back, aiming carefully to land between the trapped Investigator and the pinned-down alien head. She hacked at the dark flesh with the edge of her shield, until Frost could get her arms free again, and then between them they dug the Investigator out. The alien thrashed back and forth, convulsing down all its length, unable to get enough leverage to lift its head against the weight of the wall unit. Frost finally got her hand on her monofilament knife, and with Diana's help she cut herself free. They climbed quickly down from the alien and backed away down the corridor, both of them still spattered with its gore.

"Do you think that weight's going to hold it?" yelled Diana, shouting to be heard over the din of the alien's howls.

"Not a chance!" yelled Frost. "Let's get out of here."

She ran down the corridor with Diana at her side. Behind them they heard a crash as the alien finally threw off the wall unit. Diana tried to run faster, and couldn't. Her strength was gone, and she was running now on desperation and adrenalin. The Investigator ran effortlessly beside her, not even breathing hard, despite all she'd been through. It occurred to Diana that Frost could probably get away quite easily, but instead had chosen to run at the esper's slower pace. Frost looked round suddenly and caught the esper's eye.

"You didn't have to save me," she said brusquely. "You could have got away."

"I know that."

"Then why did you do it? Why risk your life to save mine?"

"Because you needed me," said Diana. "Now shut up and run."

"What about the invisibility? Any chance . . . ?"

"No. Not now the alien's locked on to me." She looked back over her shoulder. The alien was flowing down the corridor after them, faster than they were running, faster then they could run. Diana looked at Frost. "Don't ask. You don't want to know. Just run."

Silence's voice was suddenly in their ears, murmuring through their comm implants. "Investigator, esper, we've destroyed the heart of the alien's web. It is now completely cut off from the rest of the Base. Have you located the alien yet?"

"Oh, yes," said Frost. "We know exactly where it is."

"Good. Do you think you could lead it to where Carrion and I are at the moment? We've had an idea."

The floor plan of Level Three flashed briefly before Frost's and Diana's eyes, showing them the route.

Diana thought hard. It wasn't far. They might just make it. She looked at Frost, and nodded briefly.

"We can be there in four minutes," said Frost calmly.

"Make it three," said Silence. "We're working to a rather urgent deadline. Bring the alien here, and we'll discuss what to do next. Silence out."

"The Captain's got a plan," panted Diana.

"Yes. Interesting he didn't tell us what it was. Probably because he knows we wouldn't like it." She looked at Diana. "Can you last three minutes at this pace?"

"Shut up and keep running," said Diana.

"Are you sure you want me to do this?" said Carrion. "Once I call up the Ashrai, there'll be no turning back. I don't think you realise just how much they hate you."

"They'll hate the alien more," said Silence. "That creature and its kind threaten the existence of the whole planet. They wouldn't just destroy the forest, they'd change it into something the Ashrai wouldn't even recognise. And since the Ashrai depend on the forest for what's left of their existence, it's in their interest to side with us against the alien."

"Very logical, Captain," said Carrion. "I just hope the Ashrai are going to be logical too."

"The enemy of my enemy is my friend. Nothing like having something in common to bring two peoples together."

"You still don't understand, Captain. Once I summon up the Ashrai, they pa.s.s beyond my control. Once awakened, they might decide not to lie down again. You didn't really win here, John. You just hurt them so badly they retreated back inside themselves for a time. There's power here on Unseeli, power beyond your worst nightmares. They might decide to take on the Empire again. And this time they'd have nothing left to lose, nothing to hold them back."

Silence shook his head. "So? You're talking about billions of people on thousands of worlds. The Ashrai wouldn't stand a chance."

"John, you're talking about numbers. I'm talking about power."

"It doesn't make any difference," said Silence. "We don't have any choice. Too many things have gone wrong, and we've too many strikes against us. Frost and the esper will be here any minute, with the alien right behind them. We've run out of options, Sean. Odin, how does the countdown stand?"

"Nineteen minutes, thirty-two seconds, Captain."

Silence looked at Carrion. "Get yourself ready, Sean. We'll do it as soon as the others arrive."

They both looked round at the sound of running footsteps, and Frost and Diana came pounding down the corridor towards them. Silence looked past the women, but the corridor behind them was empty.

Diana staggered to a halt, gasping painfully for air. Frost supported her with one hand as she nodded calmly to Silence. As usual, she wasn't even breathing hard.

"The alien's right behind us, Captain. It slowed down a bit when it realised where we were going, but it's still mad enough to keep after us, once it's looked around for a trap. I take it there is a trap here, Captain?"

"Oh, yes," said Silence. "Have you hurt it at all?"

"I shot it and blew it up with grenades, and Diana dropped half a wall on it, but all we did was annoy it."

She looked round at the destruction of the alien's heart, and raised an eyebrow. "Very thorough, Captain.

You do realise that everything here will repair itself, given enough time?"

"Time is something we're all rather short of, Investigator. Before he died, Commander Starblood found time to activate the Base's self-destruct system. A small nuclear device hidden somewhere on this level is due to detonate in just over eighteen minutes."

Frost stared at him. "You're jinxed, Captain, you know that?"