Luchov grasped his ankle. It was all a nightmare - had to be a nightmare, surely - but it felt horribly real, as real as the flesh-and-blood ankle he was grasping. 'Wait! Wait! What... what is it you want to know?'

'That's better,' said Harry. He drew Luchov to his feet, took him somewhere more comfortable: an evening beach in Australia. Luchov felt the hot sand under his feet, saw a shimmering ocean with its endless lines of whitecaps, sat down abruptly as his legs gave way. He sat there in the sand, wide-eyed, shivering and very nearly exhausted. The beach was deserted. Harry looked down at Luchov and nodded. Then he stripped down to his underpants, went for a swim. When he came out of the sea, Luchov was ready to talk ...

When Luchov was finished (which is to say when Harry had run out of questions) it was getting dark. A handful of cars had come roaring down to the beach a quarter of a mile away, spilled young people with blankets and barbecue gear. Laughter and rock music came wafting on a crosswind.

'Back at Perchorsk it'll be morning, daylight,' said Harry. 'But they'll still be running around in circles looking for you. If Khuv has a locator, they'll know approximately where you are. To be absolutely sure, though, they'll go over the Projekt with a fine-toothed comb. And by now everyone involved will be very tired. One thing is certain: Khuv now knows something of what he's up against.

'Now listen: you've co-operated with me and so I'll give you fair warning. It may be that I have to destroy Perchorsk. Not for my sake or in the interest of any nation or specific group of people, but for the sake of the world. But in any case, even if anything should happen to me, eventually Perchorsk will be destroyed. The USA won't sit still for any more monsters coming out of that place.'

'Of course,' Luchov answered. 'I had foreseen that eventuality. Some months ago I passed on my warning to people in authority, made my recommendations. The warning was heeded and the recommendations accepted. Within the week, possibly as soon as tomorrow - today - trucks will start to arrive at Perchorsk from Sverdlovsk. They will deliver a new failsafe. So you see, on this one point if on no other, we are in agreement. Nothing - alien - must ever again get out of Perchorsk...'

Harry nodded. 'Before I take you back there,' he said, 'I'd like to ask you one more thing. With that space-time Gate down there in Perchorsk's guts, how come you found me so incredible? I mean, surely the two principles come pretty close? In Perchorsk you have ... a grey hole? And I make use of a dimension or space-time plane other than my own.'

Luchov stood up, stiffly brushed sand from his clothes. 'The difference is this,' he said. 'I know how the Perchorsk Gate came into being. I've worked out most of the mathematics. The Gate is a physical reality, with nothing transient or insubstantial about it. It is physical, not metaphysical. The result of an accident, yes, but at least I know how that accident happened. You, on the other hand - you're just a man! I can't understand how you could ever possibly have happened.'

Harry thought about his answer, eventually nodded. 'Actually, I believe I was an accident, too,' he said. 'The product of a one-in-a-million combination of events. Anyway, I've warned you about Perchorsk. You risk your life staying there.'

'Do you think I don't know that?' Luchov shrugged. 'Still, it's my job. I'll see it through. And you. What will you do now?'

'After I've taken you back? I have to know what's on the other side of that Gate. There has to be more there than the nightmares you've described.' There had to be, for how else could little Harry and his mother exist there? If they exist there. But what if there are other dimensions beyond that one? What if Harry Jnr has taken his mother even further afield?

Harry dropped Luchov off outside the great sliding doors of the service bays, left him in the grey morning light and the sullen snow, hammering at the wicket-gate and bellowing to be let in. Then Harry went to Luchov's quarters (which he found empty and locked from the outside), where he donned a white smock which on his last visit he'd seen hanging there. The smock was the insignia of a Projekt scientist or technician. In the garment's pocket he found tinted spectacles and put them on.

And without more ado he went straight to the magmass heart of the place, materializing on the Saturn's-rings circumference midway between two sets of manned Katushev cannons. He stayed perfectly still, held a Mobius door fixed in his mind, ready to take cover - but all seemed well. A soldier lounging against the smooth magmass wall saw him, looked a little startled, straightened up and gave a half-hearted salute. Harry stared hard at him, much to the man's discomfort, then turned and scanned the great unnatural cavern in which he found himself. Especially he stared at the blinding white sphere which was the Gate...

There were other technicians about. Everyone looked tired following their night-shift, even the gunners in their padded bucket-seats where they sighted their weapons on the Gate. Two scientists walked past Harry, talking, moving in the direction of the walkway to the sphere. One of them glanced his way as they passed, smiled and nodded in a familiar manner. Harry wondered who the man thought he was. He nodded back, began to follow the pair, and as he drew level with the walkway turned off and moved toward the centre, heading directly for the sphere of light.

Behind him a soldier shouted: 'Hey! - not in our line of fire, sir! Regulations!'

Harry glanced back casually over his shoulder and kept going. He left the outer platform behind and moved onto the walkway. Even as the gate in the electrified fence began to close, he passed through it, reached the spot where the boards were scorched. Behind him the gates opened again; footsteps came hurrying; Harry was aware of a low, angry muttering. But he was more aware of the Katushevs aimed directly at him; or rather not trained on him but on the Gate, which amounted to the same thing. 'Sir!' a voice shouted in his ear, from directly behind him.

Harry conjured a Mobius door - and with a tremor of unaccustomed panic saw that it was all wrong!

The outline of the door wasn't clear-cut in Harry's mind. Its edges shimmered like a heat-haze mirage. It floated up alongside him, drifted toward the sphere as if attracted by it, and was held there, gradually fading where it trembled above the wooden walkway. Harry had seen nothing like this before. He conjured a second door with the same result: the sphere both attracted and repelled the doors; it made them less substantial, pinned them down and broke them up. It cancelled them!

A hand fell on Harry's shoulder, and at the same time he heard shouts from the wide wooden staircase where it emerged from the magmass shaft. Someone with a high-pitched voice was screaming: 'He's here! He's here!' As the Sergeant who'd grabbed Harry's shoulder turned him about-face, he glanced toward the stairs, saw Chingiz Khuv and a second man coming down from the shaft. Harry thought: God! Doesn't that bastard ever sleep?

Khuv seemed to be holding his companion up, keeping him from toppling headlong. The man he helped was one of the espers Harry had struck while he was laying his smoke screen. And he was the one who was doing all the shouting. Then he pointed directly at Harry – screamed one last time, "That's him!' - and Khuv's dark gaze followed his shaking hand.

Khuv's eyes blazed in a moment. 'Open fire!' he shouted at once. He too pointed at Harry, shouting, 'Shoot him! Kill him! He's an intruder!'

The Sergeant who had taken hold of Harry let go of him, stepped back, went to draw the pistol at his hip. Harry moved quickly after him, drop-kicked him and sent him flying off the walkway. Falling to the boards, Harry stayed low, out of the line of fire of the Katushevs. He conjured a Mobius door level with the walkway, hanging over empty space. It was his notion to dive headlong through it - but the door shimmered and warped, was drawn up and toward the sphere of light!