The fear she felt now was something deep rooted and instinctive, an irrational and unshakeable revulsion towards things that crawled. That leant speed to Amber's mad, hobbing dash as she strove to get away from the thing chasing her through the dank, dark caverns of the city. But she could hear the thunk, thunk, thunk of her pursuer as its legs battered against the stonework, growing louder with each passing second.

Her mind was torn between the impulse to look back and see just what it was that chased her, and the knowledge that doing so would not help her in any way. But she needed to get a better look to know just what new horror she was dealing with now. Fighting through the waves of pain that tore through her leg, she tried to run as normally as she could, but was under no illusions about her chances of outrunning the thing.

So she did the only thing she could to even the odds. She started Blinking.

Amber only risked small jumps, distances of a dozen metres at a time, not wanting to tempt fate by going any further with the speed she was forced to work at. Her mind raced through small calculations of distance every second and just when it seemed the clatter from the monster's legs was closing in, she would leap ahead again. Frustrated snarling hisses echoed around her in the dark.

Only concentrating on Blink-travelling kept her mind from rolling off into full blown panic at her current situation. Ten metres, two-point-six centimetres. She flashed further ahead, taking an instant to reorientate herself again in the darkness. Hobbling with desperate speed, Amber swung around a bend and found herself facing a huge black abyss that spanned the corridor. Much too large to jump, it yawned at least ten metres in front of her, forcing her to skid awkwardly to a halt.

Casting one fearful glance behind, she swallowed a deep breath, estimated the distance she needed to clear and made the Blink happen. Done in haste, Amber had a moment of terrifying weightlessness as she re-emerged into real space. Then her boots thumped against the stone and she exhaled a sigh of relief.

Another deafening hiss tore through the passage, causing her to turn sharply, carbine levelled in shaking hands. Now she did get a good look at her pursuer and wished she hadn't. It was definitely an arthropod, with a thick rigid exoskeleton and ten limbs that she could see. Its torso had a barrel-like shape and the legs arched out from it in five segments like a spider's. She could now see in the light that its huge head sported a pair of colossal fangs as well as a gaping jaw. Rivulets of water dripped from its ridged armour, creating an eerie echoing drumbeat.

For a moment the monster just stood there, its cluster of eyes glaring out at her. Amber started edging backwards, wondering if the thing could get across to her. She reasoned that it was not a good idea to wait and find out. But then the creature bunched its legs towards its body in a way that could only mean one thing.

Amber's heart stopped for an instant as the terrifying colossus jumped towards her, its bulk casting a shadow over her diminutive form as it flew across the gap with ease. Just before those fangs slammed down into her, she forced another short Blink, vanishing in the nick of time. She reappeared several metres further down the passage and saw the arthropod smash into the solid stone of the floor. Another vicious hiss reverberated around the walls as it scrambled back onto its many feet.

Amber got the distinct impression that the predator was getting angry.

So she started running again, blundering on through the darkness. The rational part of her mind started to kick in now though, as she kept Blinking ahead of her pursuer. She couldn't keep this up, not indefinitely, and she had no idea how long the spider-creature would be able to follow. She needed a way out, and fast.

As she ran she reached slung her pack onto one shoulder, bringing it round in front of her so she could delve into it and free the alien mapping console. Swinging the pack across her back again, Amber squeezed the activation switch, bringing up the display of the section she was currently hurtling through. Behind the glowing blob that showed her position, a much larger reading thundered along ominously.

Trying not to look at it, Amber focused on finding a route that would take her out of this level and beyond the thing's hunting grounds – if there was such a thing. Three corridors away she spotted something that looked like one of the elevator stations and a burst of energy shot through her. If it was working it spelled the single quickest way out of her current predicament.

Distracted as she looked at the screen, Amber caught her foot on a spur of broken masonry and with a panicked yelp she pitched forward, sliding headlong across the water-slick floor. The pad went skidding away from her as she released her grip on it to break her fall. She frantically scrambled back to her knees, and saw the huge shadow of the monster seep across the floor around her – the tapping of its feet in her ears.

Plunging one hand into her pack, she dragged the one remaining glow node free and twisted it into life. Light exploded over her and she pivoted on the spot, hurling the blazing globe in one fluid motion. Her instinct paid off as the node smashed the onrushing arthropod squarely in its hideous face. While it didn't do any physical damage, it stunned the creature for just a moment and it reared its immense bulk away from the glare of the glow node, hissing furiously.

Amber took the opportunity, scrabbling away from it and back onto her feet, sweeping up the fallen pad as she went. She didn't wait to see the full results of her desperate diversion, instead locking her eyes onto the route to the elevator and sprinting as fast as her aching leg would allow.

The node bought her enough time to open out a gap without having to Blink any further, and by the time the monster had managed to catch up again she was within sight of the elevator station. It glittered with power, as though inviting her in, and she put on a final burst of speed to reach it . A fierce determination put fire in her veins. So close to safety.

Hurling herself into the open elevator she barely glanced at the panel, simply smacking the first green section with a wild swipe of her hand. She pivoted, back-pedaling up against the far wall and levelling her carbine at the huge shape that clambered down the passage towards her. The torch on her gun lit up the primeval head of the predator and she squeezed the trigger.

She might have been terror-stricken and charged with adrenaline, but that didn't stop her from firing a superheated ceramic lance straight through one of the creature's eyes. It reared back with a horrible, deafening sound, halfway between a screech and a roar. It crashed into the nearest wall and before it could right itself the elevator wrenched Amber away with ferocious speed.

With her injured leg she couldn't stay upright against the sheer force and found herself flung hard into the wall. The impact juddered through her whole body before she slammed to the floor with a gasp of pain. Squeezing her eyes shut, she simply lay there and prayed for a safe delivery to wherever the elevator was taking her.

The jolt when it stopped sent her rolling until she hit the far wall, and a bolt of pain shot up her spine. Amber coughed for breath, staying curled in the foetal position as the elevator door slid open. Light from the corridor beyond gushed into the confined space and she squinted against the sudden glare. Seconds ticked by and she felt her chest rising and falling in ragged, heaving breaths. Her heartbeat thundered in her ears like a hundred drums and for what felt like an age she couldn't bring herself to move.

All the horror, fear and panic that she had been forcibly controlling suddenly escaped from her body in the form of a scream that burned her throat and wracked her body like an electric shock. It lasted for as long as her lungs could take and when the echo finally died she slumped limply against the floor.

Amber didn't know how long she lay there recollecting her composure. Eventually she forced herself to her knees with a groan of effort, feeling a dull ache in every part of her. Still, she was alive, and right now that was all that mattered.

Struggling to her feet, she could feel her legs shaking from the adrenaline. What the hell had just chased her through the depths? It looked like some sort of giant spider ... then it hit her. The murals, the carvings all over the city – could they have been some kind of warning about such a beast? Or did the previous inhabitants of the city attach some sort of religious significance to those monstrosities? Whatever the case, it seemed like too much of a coincidence to comfortably ignore.

Stepping out into the passage she cast a cursory glance around with her carbine. The massive vaulted halls of the upper levels now filled her with a sense of safety. Well-lit and apparently undamaged, this passage bore no resemblance to the monster-filled labyrinth below. She looked back into the elevator. The thing wouldn't even have fit inside it, even if by some miracle it had the inkling to try. She sucked in a shuddering breath, regaining control of her body. Her heartbeat started to slow to its normal level and her limbs gradually stopped trembling.

So, onto the next problem. Now where the hell am I? She might have been safe for now, but it wouldn't do her any good if she couldn't find the others. Glancing down at the map she at least had a floor plan to guide her locally, but when compared against the vastness of the city itself the personal display wouldn't help a whole lot. Then a thought occurred to her. She was higher up now, out of the shielded depths that probably would have blocked her communications anyway.

"This is Operative Amber Garret," she forced into the radio. "Blink ID Alpha Hammer Five. Is anyone receiving me?"

Yet again only silence greeted her plea. Frustration seeped through her and with a snarl she slammed a clenched fist against the nearest wall, accomplishing nothing except hurting herself. She bit back a stream of curses and made herself focus. If an avalanche and a giant spider couldn't finish her off, a bit of navigation should be child's play.

Now that she actually had a chance to examine the alien device, she set about trying to get it to zoom out and display a larger area of the city. For a few minutes she fruitlessly crashed through various menus in alien language, managed to recolour the filter on the screen half a dozen times, and caused what looked like some kind of warning message to flash up, blocking her view. Working back through her progression each time, she started learning her way around the interface, but still couldn't get a larger view of her position.

However, just as she was about to give up and just pick a random direction she must have hit something along the right lines. A small white bar appeared on the right of the interface with a dot sitting at its centre. Amber pressed her index finger against it and slid gently upward. A small, almost hysterical laugh escaped when the display started to retract, showing a larger section of corridors. She continued until the zoom was around three quarters of the way to the top before something caught her eye and she stopped.

Six dots moving together. In formation.

No way. Could she be that fortunate? The only things that would possibly make that kind of reading were other Blink operatives – she was certain! The creatures that infested this under-water hell hole were many things, but organised wasn't one of them.

With a revitalised spring in her step she set off towards them, hoping, praying that her deduction was right. Limping along quickly and quietly she twisted and turned through several passages and hauled herself up a flight of stairs to reach the same level as the other signals. They were moving towards her, and as she watched the dots on the screen her suspicions were confirmed. She recognised the two-by-two cover formation that she herself had used often enough as part of Hammerhead Squad.

Amber slowed as she approached the final junction in the corridor. A glance at the alien mapper told her that the other operatives should be just around the corner. Even now, however, as certain as she was, a tiny kernel of unease remained burning in her gut. After everything that had happened she simply couldn't take it at face value. Halting at the corner for a moment, She took a deep breath before stepping slowly out into the adjoining section, aiming her carbine down the passage.

And she found herself face to face with the operatives of Tundra Squad.