It was the cold that awoke me: a cold that sapped the strength from me and left me with limbs that ached. I levered myself into a sitting position and opened my eyes.

It took a minute for my vision to clear. This alone confirmed my opinion that I had been insensate for a considerable period. As I regained my focus, it was obvious that I was no longer in the basement of the engineering faculty. Instead, I was on the shore of a strange lake. Red, sandy soil coated my hands and my clothing. A violet star hung in the sky above me, sending shadows across the landscape and turning my flesh a necrotic hue. On the other side of the lake was a city of tall towers that was surrounded by a walled labyrinth. It was obvious that the city was inhabited, for I could see lights glimmering from the towers.

Professor C_ was lying a short distance from me, sprawled across a patch of scrub that the unknown force which had brought us here had seen fit to deposit him on. I shuffled across to him and soon determined that he was still alive. It was not long before he too was awakened, and I helped him to his feet. I could see fear and panic were threatening to overtake him, so I tried to give him some reassurance. "Look! A city! I am sure that we will find help there."

The professor shook his head violently and pushed me away. "No! You don't understand! I can't go back there!"

"Why not? You mean to say that you have been here before?" I was astonished at Professor C_'s revelation. Still, if he had been to this alien realm and returned safely (in body, if not in mind), then I would have been a fool to abandon him or to let him escape from me. I grabbed at his sleeve in an attempt to restrain him. "Professor, surely we have nothing to fear? Even if that city is a den of corruption or awfulness, is it not better to be in shelter than in the open in an unknown land?"

Professor C_ shuddered and stared towards the towers. "Ah, W_. If only you understood what you have done. You were meant to come here, as I once did. The machine wanted you, as it did me: a new disciple to spread its message. There are terrible things in there - terrible things! But the labyrinth is the only way to enter the city, and the city is the only way to leave this cursed land."

"Then our course is obvious."

"No. If I was to re-enter that labyrinth, it would be my end."

"But you must have traversed it! If you came here before ... ?"

"Which I did."

"... Then you have gone through the labyrinth and survived whatever terrors lie within it. Surely they cannot be that awful?"

I looked at Professor C_, hoping that he would see reason. Instead, he shook his head and set his face against mine.

"I will not."

"Very well."

And, with that, I turned from him and marched towards the alien towers that waited for me on the far side of the lake.

As there was no way to cross the lake, I elected to walk around its shores. I had no sense of how far away the city was; scale did not appear to work in this place as it did elsewhere. No matter how long I walked for, the strange towers did not appear to come closer. At one point I looked back along my path in order to gauge how far I had gone. All I could see was the lake, surrounded by an infinite desert, the violet star reflected in its still waters. There was no sign of Professor C_. As far as I could tell, I was alone save for the inhabitants of those mysterious towers.

The land around me was silent, except for the sounds of my footsteps in the sandy soil and the noise of the wind as it blew the dust before me. At one time I was sure that I heard something rise from the waters of the lake but, when I turned to look, there was nothing to be seen; not even ripples to disturb its eerie calm. So, I fixed my gaze upon the city and continued to walk.

Time had no meaning here; there was no means by which I could measure the passage of time. Somehow, in my journey from that London basement, my watch had ceased to function. Its casing was intact and there was no clue as to the nature of the damage it had sustained. The strange star that served as the sun in this place did not move in the sky. I tried to count my footsteps in an attempt to define my progress around the lake, but I lost count as I could not concentrate. Thus, it was a surprise to me when I arrived at the city walls.

It was as if the walls of the city had been carved from a single block of stone. There were no joins or breaks in the titanic structure, nor could I sense any as I ran my fingers along its grain. I glanced long its length, trying to judge which way I should turn. Eventually, I decided to walk away from the lake. I was still uneasy at the thought of what might lurk in its otherwise tranquil waters.

I turned my back to the lake and urged my tired limbs further on. I needed to find food and shelter; if I did not, I was sure that I would perish in this unknown place. Then, I spied a breach in the wall: a crack that was just wide enough to admit me. I hesitated, unsure as to whether it was better to face the unknown than to continue in that desert. Would I find another entrance, one that would allow me to present myself to the denizens of the city and beg their mercy? I did not know. I held myself at the edge of the opening and stared into the unfathomable darkness beyond. Then, as if of their own accord, my limbs propelled me forwards.

I stumbled into the passage, my senses straining to catch any hint as to what awaited me. Blindly reaching ahead of me, I felt the rock that surrounded me. It was smooth and cool to the touch, a comfort after the heat of the desert. I moved forward cautiously, letting my hands guide me. My eyes struggled to find something on which they could focus. As I became accustomed to the darkness, I became aware of a dim glow ahead of me.

I crawled forward through the ever-narrowing passage, heading towards the light. It was the only landmark in the underworld, and felt that I had no choice but to continue towards it. I carried on, my eyes streaming from the pain of the contrast between the light ahead of me and the darkness surrounding me. Suddenly, the passage dropped away, sending me tumbling into a cavern. I fell, sprawling across the rocks, until I landed bruised and battered and in a heap.

The pain of my landing caused my vision to cloud momentarily. When it cleared I saw that I was in a long corridor, seemingly hewn from the rock beneath the strange city. Tiers of cells lined the corridor, their openings illuminated from within. This, I concluded must have been the source of the light that had sustained me in the netherworld I had just come from. I turned back to see where I had fallen from, but all I could see was the passage stretching behind me into infinity.

My mind reeled. Had I fallen from nowhere, or had the world changed around me? I spun around in a panic, desperately searching for the cleft that had spewed me into this place. When it dawned on me that it had gone, I must have uttered a cry of astonishment or protest for, in response, I heard moans of pain and fear coming from the cells. I crept towards one of the openings, intent on seeing what - or who - lay within.

The cell was small and illuminated by a lantern that was suspended above the door. Its light was cast into every corner of the cell so that I could see everything within. The floor and walls were bare, showing nothing but the rock and its natural contours. In one corner of the cell was a pair of earthenware bowls, both stained and battered from unknown years of use. In the opposite corner was a bundle of rags, coloured grey and brown and green. As I watched, the rags moved and I could see a human form beneath them - a twisted and diseased human. Its limbs were spindled and knobbed; the skin was loose and covered with sores that oozed from beneath broken crusts. The face was hollow and covered in sallow pox scars; the eyes were sunken and filmed. The wretched figure reached out towards me with both arms and called out, "Help. Me."

My instinct was to recoil from the figure, disgusted by its scabrous wounds, but my training as a doctor gave me the strength to do otherwise. I walked forward and knelt beside the figure, murmuring words of reassurance and comfort. My fingers picked at the rags, pulling the flesh beneath them. The cell filled with the stench of bodily corruption. Quickly, I scurried for one of the bowls, hoping to find some water with which to clean the sores on this pathetic creature's limbs. As I did so, I felt a tugging at my sleeve.

Another of the piteous creatures - a near twin to the one in the cell - was standing in the doorway. A clawed hand clutched at the sleeve of my jacket. The second figure moaned at me. "Help. Me."

I nodded. "I will, just as soon as I have seen to this fellow."

The second figure seemed not to have understood me as it pulled at me once more, this time more violently than the last. I fell, cracking the earthenware bowl on the stone floor. The occupant of the cell moaned at this loss of one of his possessions. I decided that I would have to be firm. "You must wait your turn! I will see to you as soon as I have dealt with this poor soul!"

I reached out to pull the hand from me, to free myself from its foul grasp. As I did so I could see more figures, in the doorway and beyond, all of them reaching for me. From a dozen or more cracked throats, identical words rang out in a ragged chorus.

"Help. Me."

"Help. Me."

"Help. Me."

"HELP! ME!"

This last came from a hulking figure that had pushed its way to the front of the throng, scattering its fellows before it like chaff before a storm. I stared in horror at its degenerate form as it reached towards me, pulling me into its bosom. The stench of rotten flesh assailed my nostrils and I cringed at the creature's touch. Blind panic overtook me.

My hands must have grasped a cobble from the floor, for the next thing I knew was that I was pounding at the face of this horror. The stone that I held in my hands was slick with blood and other bodily fluids, and thing's head was a mess of pulp and broken bone. It moaned piteously and staggered back, collapsing in a diseased heap. As I realised what had happened, I cried out and ran from that place, unable to face the destruction that I had wrought on one that had sought my help.