There was a sound behind him. Without turning, Samlor lashed out with a boot. His hobnails ground into something warm and squealing where his eyes saw nothing at all. He paused for a moment to finger his medallion of Heqt, then continued. The skittering preceded him at a greater distance.

When the tunnel entered a shelf of rock it broadened suddenly into a low ceilinged, circular room. Samlor paused. He held his lamp out at arm's length and a little back of his line of sight so that the glare would not blind him. The room was huge and empty, pierced by a score of doorways. Each but the one at which Samlor stood and one other was closed by an iron grate.

Samlor touched but did not draw his double-edged dagger. 'I'll play your silly game,' he whispered. Taking short steps, he walked around the circumference of the room and out the other open door. Another empty passage stretched beyond it. Licking his lips again, Samlor followed the new tunnel.

The double clang of gratings behind him was not really unexpected. Samlor waited, poised behind his knife point, but no one came down the stone boring from either direction. No one and no thing. Samlor resumed walking, the tunnel curving and perhaps descending slightly with each step. The stone was beginning to vibrate, a tremor that was too faint to be music.

The passage broadened again. This time the room so formed was not empty. Samlor spun to face what first seemed a man standing beside the doorway. The figure's only movement was the flicker of the lampflame over its metallic lustre. The Cirdonian moved closer and prodded the empty torso. It was a racked suit of mail, topped by a slot-fronted helmet.

Samlor scratched at a link of the armour, urged by a suspicion that he did not consciously credit even as he attempted to prove it. The tightly-woven rings appeared to be of verdigrised copper, but the edge of Samlor's knife could not even mar the apparent corrosion. 'Blood and balls,' the caravan-master swore under his breath. -

He was touching one of the two famed suits of armour forged by the sorcerer Hast-ra-kodi in the fire of a burning diamond. Forged with the help of two demons, legend had it; and if that was open to doubt by a modern rationalist, there could be no doubt at all that the indestructible armour had clothed heroes for three of the five ages of the world.

Then, twelve hundred years ago, the twin brothers Harash and Hakkad had donned the mail and marched against the wizard-prince Sterl. A storm overtook the expedition in the mountains; and in the clear light of dawn, all had disappeared - armour, brothers, and the three thousand men of their armament. Some said the earth had gaped; others, that everything had been swallowed by the still-wider jaws of airy monsters whose teeth flashed in the lightning and whose backs arched high as the thunderheads. Whatever the cause, the armour had vanished in that night. The reappearance of one of the suits in this underground room gave Samlor his first tangible proof of the power that slunk through the skittering passages.

From the opening across the room came the sound of metal scraping stone, scraping and jingling. Samlor backed against the wall, sucking his cheeks hollow.

Into the chamber of living rock stepped the other suit of Hast-ra-kodi's armour. This one fitted snugly about a man whom it utterly covered, creating a figure which had nothing human in it but its shape. The unknown metal glowed green, and the sword the figure bore free in one gauntleted hand blazed like a green torch.

'Do you come to worship Dyareela?' the figure asked in a voice rusty with disuse.

Samlor set his lamp carefully on the flooring and sidled a pace away from it. 'I worship Heqt,' he said, fingering his medallion with his left hand. 'And some others, perhaps. But not Dyareela.'

The figure laughed as it took a step forwards. 'I worshipped Heqt, too. I was her priest - until I came down into the tunnels to purge them of the evil they held.' The tittering laughter ricocheted about the stone walls like the sound caged weasels make. 'Dyareela put a penance on me in return for my life, my life, my life ... I wear this armour. That will be your penance too, Cirdonian: put on the other suit.'

'Let me pass, priest,' Samlor said. His hands were trembling. He clutched them together on his bosom. His fighting knife was sheathed.

'No priest,' the figure rasped, advancing.

'Man! Let me pass!'

'No man, not man,' said the thing, its blade rising and a flame that dimmed the oil lamp. 'They say you keep your knife sharp, suppliant - but did gods forge it? Can it shear the mesh of Hast-ra-kodi?'

Samlor palmed the bodkin-pointed push dagger from his wrist sheath and lunged, his left foot thrusting against the wall of the chamber. Armour or no armour, the priest was not a man of war. Samlor's left hand blocked the sword arm while his right slammed the edgeless dagger into the figure's chest. The bodkin slipped through the rings like thread through a needle's eye. The figure's mailed fist caught the Cirdonian and tore the skin over his cheek. Samlor had already twisted his steel clear. He punched it home again through armour, ribs, and the spongy lungs within.

The figure staggered back. The sword clanged to the stone flooring. 'What-?' it began. Something slopped and gurgled within the indestructible helmet. The dagger hilt was a dark tumour against the glowing mail. The figure groped vainly at the knob hilt with both hands. 'What are you?' it asked in a whisper. 'You're not a man, not...' Muscles and sinews loosened as the brain controlling them starved for lack of oxygen. One knee buckled and the figure sprawled headlong on the stone. The green glow seeped out of it like blood from a rag, staining the flooring and dripping through it in turn.

'If you'd been a man in your time,' Samlor said harshly, 'I wouldn't have had to be here now.'

He rolled the figure over to retrieve his bodkin from the bone in which it had lodged. Haemorrhages from mouth and nose had smeared the front of the helmet. To Samlor's surprise, the suit of mail now gaped open down the front. It was ready to be stripped off and worn by another. The body within was shrivelled, its skin as white as that of the grubs which burrow beneath tree bark.

Samlor wiped his edgeless blade with thumb and forefinger. A tiny streak of blood was the only sign that it had slipped between metal lines to do murder. The Cirdonian left both suits of armour in the room. They had not preserved other wearers. Wizard mail and its tricks were for those who could control it, and Samlor was all too conscious of his own humanity.

The passageway bent, then formed a tee with a narrow corridor a hundred paces long. The corridor was closed at either end by living rock. Its far wall was, by contrast, artificial - basalt hexagons a little more than a foot in diameter across the flats. There was no sign of a doorway. Samlor remembered the iron grates clanging behind him what seemed a lifetime ago. He wiped his right palm absently on his thigh.

The caravan-master walked slowly down and back the length of the corridor, from end to end. The basalt plaques were indistinguishable one from another. They rose ten feet to a bare ceiling which still bore the tool-marks of its cutting. Samlor stared at the basalt from the head of the tee, aware that the oil in his lamp was low and that he had no way of replenishing it.

After a moment he looked down at the floor. Struck by a sudden notion, he opened his fly and urinated at the base of the wall. The stream splashed, then rolled steadily to the.right down the invisible trench worn by decades of footsteps. Thirty feet down the corridor the liquid stopped and pooled, slimed with patches of dust that broke up the reflected lamplight.