The water was icy cold, but after the first shock Blade found it refreshing. It scoured away some of the grime and sweat, eased the aches and pains, and left him feeling a great deal better.

His feet were just touching bottom on the far side of the river when a hissing scream sounded high overhead. Blade dove forward, getting underwater without making a splash. Then he poked his head above the surface, just as the scream came again, three times in rapid succession.

Looking up, Blade saw a weird shape sail across the sky. It reminded him of a slim mountain lion with tufted ears and long clawed legs. Heavy ribbed membranes like bat wings extended between the legs, giving enough lifting surface to support the beast in the air. The creature glided across the sky like an immense flying squirrel, steering with its short fat tail.

Blade counted nine more of the bat-cats before the last one disappeared. He faintly heard more screams from well upstream, where they seemed to have landed, then growling which slowly faded away. It sounded as if the beasts were feeding. On what, Blade didn't know, but knew he'd better be careful or the next time it might be on him. The bat-cats were large enough to be dangerous opponents for an unarmed man, even if they hadn't hunted in packs.

Blade headed downstream again, staying in the water for a few hundred yards to avoid leaving a trail. Then he climbed out of the water, exercised vigorously to warm himself up and unkink his muscles, and kept going.

The sun went down in an awesome display of orange, purple, and red which seemed to cover half the sky. Blade kept moving until the light was nearly gone and even his superb night vision could barely make out the ground in front of him. Then he found a narrow V between two roots of a large tree, drifted full of dead leaves. He crept in on hands and knees, settled himself with his back against the trunk, and piled over his legs and stomach all the leaves he could reach.

It wasn't much protection, and he could only hope that none of the bat-cats would come by while he slept. It was still better than stumbling on through the night, more tired and chilled with each mile.

Blade slid lower into the leaves, piled more over his chest, then lay back to sleep.

Blade awoke when the sky was still a dirty gray, as a familiar sound blasted across the forest and jerked him out of sleep. It was the roar of a low-flying jet plane.

Blade sprang to his feet, wide awake and looking around for the nearest spot where he could see the sky. A quick look told him there wasn't any nearer than the riverbank. He dashed down the slope, narrowly missing trees, leaping over stumps and fallen logs, reaching the open just as the sound of the jet faded away to the south.

Before he could draw in enough breath to curse, he heard more jets approaching from the north. He had time to step back into the trees far enough to see without being seen. Then the jets raced overhead less than a thousand feet up. They were flying slowly enough to give Blade a good view of them.

He'd heard of drawing-board projects like these jets, but he'd never seen or heard of anything like them getting off the ground anywhere in Home Dimension. The fuselages were disk-shaped, flattened and nearly as wide as they were long. Twin rudders jutted up from the rear of the disk, and on either side projected short swept-back wings.

A pair of jet engines was sunk into the root of each wing and a cluster of gray cylinders looking unpleasantly like bombs hung from a rack near each wingtip. The undersides of the planes were blue-gray and the tops camouflaged in blobs and stripes of green and brown. There was some sort of insignia on the wings, but the planes were gone before Blade could make it out.

The whistle and roar of the jets died away. Blade walked a little farther under the cover of the trees before sitting down to think. He didn't want to run any risk of being spotted now. If those gray cylinders were really bombs, each plane was carrying enough to demolish a good stretch of forest if they thought he was a suitable target.

He wished he'd been able to make out the insignia on the planes. It would have answered one awkward question. Those jets looked odd, but they were at about the same technological level as Home Dimension. Blade knew only one world in Dimension X where this was so-the strange world where an other-England called the Empire of Englor fought an other-Russia called Russland. Was he back in that Dimension, one of the weirdest and deadliest he'd ever visited?

If he was, he might have a problem. The presence of the jets suggested he was in territory ruled by one or the other of the two great powers. There was no wilderness like this anywhere in Englor or any of its allies, as far as he knew. Was he in Russland or some Russland satellite?

If he was, he was in danger. The rulers of Russland were an iron-fisted military elite called the Red Flames. Their policy toward strangers was shoot on sight-unless they wanted to ask a few questions, in which case the stranger was better off being shot. If he was in Russland, by some quirk of the computer or the unknown forces governing Dimension X, he might actually be better off playing Tarzan in the wilderness until the time came for him to return home.

However, three mysterious jet planes did not make a Russland. Blade laughed at his own overactive imagination. He couldn't afford to spend too much time worrying about unanswerable questions. This Dimension had a civilization, that civilization was technologically advanced, and he was going to find it. He was also going to keep out of sight as much as possible on his way to find it.

That was enough for the moment. Blade found a branch lying on the ground, large enough and sound enough to make a good club. He shouldered it and set off, still heading downstream.

For the next three days Blade tramped steadily downstream, never more than a hundred yards from the riverbank and never that far from the cover of the trees. He didn't risk a fire, but there was plenty of food to be eaten raw. He found berries, edible mushrooms, a small reddish fish, and something like a rabbit-sized squirrel with long floppy ears. None of them tasted very good, but together all of them kept him alive. After the second day he had enough skins from the squirrel-rabbits to make himself sandals and a loinguard.

The winged-disk jet planes passed low overhead at least once each day. Sometimes they carried the gray cylinders, at other times large yellow tanks. Twice Blade saw the vapor trails of other jets flying too high to be identified, and once he heard something that sounded vaguely like a helicopter. Once he heard a more ominous sound in the distance, a series of echoing roars like explosions.

On the fourth day Blade reached a point where the river broke through the foothills of the mountains, forming a rugged canyon. He had an all-day struggle to get through the canyon. Several times he ended up clinging by fingers and toes to sheer rock faces with long drops to the rapids below him. Both his grip and his luck held. By late afternoon he was out of the canyon, facing the wooded lowlands beyond.

A plane flew overhead as Blade made camp that night, lower than usual and cruising slowly so he was able to make out the insignia. The plane bore a green triangle with a red border and golden wings, not the insignia of the Russlanders or any of their allies. This was a new Dimension with a new, unknown people. Blade slept better that night than he'd done the first three nights, because of the good news and because it was warmer down here in the lowlands. Sandals and a fur loinguard didn't do much to keep off the night breezes.

He was on the move before dawn the next day. As it grew light he bathed and caught three fish for breakfast. An hour after breakfast he reached open ground. An hour farther on, much of the relief he'd felt at learning he wasn't in Russland suddenly vanished.