Pauncho van Veelar and Barney Banks had had a big shock when they saw Doc Caliban in 1968 after five years' absence. Of course, they had always remarked on how young their 'Uncle Doc' looked. But seeing him again had brought up some very disturbing questions. How could a man born in 1901 still look thirty years old or younger? He should show some signs of ageing! And so Doc Caliban, who desperately missed his old side-kicks, no matter how self-sufficient he seemed to others, took their sons into his confidence. They would have joined him just to be able to get into the most exciting life on Earth and to follow in the footsteps of their beloved-hated fathers. But the chance of becoming immortal would have been more than enough inducement.

Barney had picked up two rifles and extra magazines of 20 rounds each. Doc said, Thanks,' and inspected his rifle for working order. Pauncho finished taping the mouth, wrists, and ankles of the sleeping guard. Doc said, 'If my suspicions are correct, Iwaldi will be making for his underground labyrinth. He'll probably leave the way open so his enemies will follow him down. They'll find out why he's so hospitable.'

They had just entered the next room when they heard and felt the explosion. The floor quivered, and air moved against their faces. Two rooms on, they came to an entrance made by a section of wall sliding back. Faint streamers of smoke and an odour of dynamite were being breathed from the dark mouth. Doc removed from his vest pocket a cap with a small tube atop it and put it on his head. Then he unfolded dark goggles from the same pocket and put them on. The others also put on caps and goggles, and then they went into the tunnel. This was unlit, but it did not impede them. The device atop the can projected a 'dark light' and their special goggles enabled them to see whatever the light hit. They had contact lenses which would do the same work, but these required time and effort to get in and out, and they preferred the goggles in this situation because they could be ripped off if the situation demanded.

The tunnel curved away from the entrance and then straightened out. The smoke got thicker. They inserted nose plugs to filter it. Thirty feet past the bend, they came to the entrance of a vertical shaft. Doc went down the steel ladder first, his backpack rubbing against the stone wall of the shaft behind him. He counted forty rungs about a foot apart before he stepped onto the bottom of the shaft. A horizontal shaft joined it, leading in an easterly direction. It was designed for dwarfs or designed to make men of normal stature uncomfortable. All three had to duckwalk for thirty yards before they came to a place where they could straighten up. This was a forty-foot square room, carved out of granite, furnished only with corpses.

These were near the opposite doorway. Apparently they had touched off some kind of trap loaded with explosives. Doc counted the bodies. Eight. That left eighteen. The bazooka team was not among them. He would have to be cautious about going too fast, since the survivors would, be proceeding slowly now. How-ever, the explosives in that confined area must have deafened and injured others, and the effective number of fighters in their party should be cut down. Also, it was possible that they would get cold feet, for which he could not blame them, and would return. To run head-on into them in these cramped tunnels could be fatal to his small party. But there was nothing to do but push on.

They walked bent-kneed through a thirty-five foot tunnel which ended when it joined another tunnel at right angles to it. Doc squirted some vapour for several yards down both directions. Suddenly, glowing foot-prints - glowing only because the goggles revealed them - sprang out. But the prints were in both directions, and Doc did not have any way of separating the Iwaldi party's prints from those of the invaders. It was true that Iwaldi was not over four feet five inches high, but his feet were disproportionately large. Nor was there any way of determining the weight of the person who had left prints. The vapour settled on the floor and was illuminated only where there was a difference in elevation of the material of the floor itself. Even a difference of two microns briefly illuminated the powder. There was enough dust on the floor for the boots to make some impressions.

The prints indicated that their makers had been going and coming on both sides of the tunnel at right angles to the one from which they had just emerged.

Doc cast up and down the tunnel for thirty yards. There were many more prints to the right, and then he found a stain of blood on the side of the wall to the right. He turned and beckoned to the two men, who could see him plainly in the radiation cast by their projectors.

'It's possible that they split up and some went the other way,' he said.

Twenty yards further, the tunnel made a turn to the left. After another twenty yards, they found the tunnel almost completely blocked. A section of solid stone, three feet high and twenty long, had thrust itself out of the wall on the right and crushed a number of men against the left wall. Doc removed his pack and shoved it ahead of him while he crawled between the top of the block and the ceiling of the tunnel. He counted eight heads, most of which were above the stone, the bodies being squeezed into forms three inches wide. That left ten ahead, if the party had not split up.

'If I was them, and I'm glad I'm not,' Pauncho said, 'I woulda taken off by now.'

'Maybe you shouldn't try to get through there,' Barney said in a mock solicitous voice. 'With that belly, you'll get stuck, and I won't be able to get by you. You stay here and guard my rear.'

Pauncho chuckled, and the echoes came back from ahead. Doc said, 'Sh!', but Pauncho whispered, 'Any tune I get a chance -'

He stopped when Doc repeated his warning. Then he heard the noises, too.

Pauncho did have some trouble getting his huge belly through, and he was huffing and swearing when he fell off the other end of the block. By then the yelling and screaming of men and the weird shrill cries had increased. They duckwalked swiftly, Pauncho groaning softly and swearing that he would quit drinking beer if he ever got a chance to drink beer again. The tunnel bent at ninety degrees to the right, continued for ten yards, bent ninety degrees to the left, continued for twenty yards, and then they were at the arched entrance to a room so large it could almost be called a cavern.

It was lit only by the flashlights of the men inside but Doc's blacklight enabled him to see everything clearly. He removed the goggles for a moment so he could get an idea of how the situation looked to the men. The beams shot here and there and then dived for the floor, lay there shining, and were picked up again, though not always by the one who had dropped them. Some of the beams briefly illuminated large birds: white snow owls, golden eagles, bald eagles, African vultures. They swooped through the beams, their eyes flashing redly, their wings beating loudly, their talons outspread. Some closed in on the holders of the flashlights as if they were riding the beam down to their target. The butts of rifles flashed; one struck an eagle on the wing, and the great bird fell out of sight.

No rifles were being fired. Apparently the men were afraid of ricochets. They were using the weapons as clubs. But the birds did not seem discommoded by either the darkness or the lights shining in their eyes. They attacked from all angles, and men went down screaming under their beaks and talons.

Doc replaced his goggles.

The birds uttered no cries whatsoever. They were as silent as the wolves that had attacked Caliban's group in the bedroom. It was this that caused Caliban to look for the tiny hemispheres attached to the tops of the birds' heads.