"So... it is the edge... of the world!" he said.

Chryseis did not answer him. She trotted ahead of him, looking over the side of the cliff, halting briefly now and then to examine the rim.

"About sixty yards more," she said. "Beyond those trees that grow right up to the edge."

She started running swiftly with him close behind her. At the same time, a gworl burst out of the bushes growing on the inner edge of the hill. He turned once to yell, obviously notifying his fellows that he had found the quarry. Then he attacked without waiting for them.

Wolff ran toward the gworl. When he saw the creature lift its knife to throw, he hurled the horn at it. This took the gworl by surprise—or perhaps the turning horn reflected sunlight into his eyes. Whatever the cause, his hesitation was enough for Wolff to get the advantage. He sped in as the gworl both ducked and reached a hand out for the horn. The huge hairy fingers curled around the horn, a cry of grating delight came from the creature, and Wolff was on him. He thrust at the protruding belly; the gworl brought his own knife up; the two blades clanged.

Having missed the first stroke, Wolff wanted to run again. This thing was undoubtedly skilled at knifefighting. Wolff knew fencing quite well and had never given up its practice. But there was a big difference between dueling with the rapier and dirty in-close knivery, and he knew it. Yet he could not leave. In the first place, the gworl would down him with a thrown blade in his back before he could take four steps. Also, there was the horn, clenched in the gnarled left fist of the gworl. Wolff could not leave that.

The gworl, realizing that Wolff was in a very bad situation, grinned. His upper canines shone long and wet and yellow and sharp. With those, thought Wolff, the thing did not need a knife.

Something goldenbrown, trailing long black-andauburn-striped hair, flashed by Wolff. The gworl's eyes opened, and he started to turn to his left. The butt end of a pole, a long stick stripped of its leaves and part of its bark, drove into the gworl's chest. At the other end was Chryseis. She had run at top speed with the dead branch held like a vaulter's pole, but just before impact she had lowered it and it hit the creature with enough speed and weight behind it to bowl him over backward. The horn dropped from his fist, but the knife remained in the other.

Wolff jumped forward and thrust the end of his blade between two cartilaginous bosses and into the gworl's thick neck. The muscles were thick and tough there, but not enough to stop the blade. Only when the steel severed the windpipe did it halt.

Wolff handed Chryseis the gworl's knife. "Here, take it!"

She accepted it, but she seemed to be in shock. Wolff slapped her savagely until the glaze went from her eyes. "You did fine!" he said. "Which would you rather see dead, me or him?"

He removed the belt from the corpse and fastened it on himself. Now he had three knives. He scabbarded the bloody weapon, took the horn in one hand, Chryseis' hand in the other, and began running again. Behind them, a howl arose as the first of the gworl came over the edge of the hill. However, Wolff and Chryseis had about thirty yards' start, which they maintained until they reached the group of trees growing on the rim. Chryseis took the lead. She let herself face down on the rim and rolled over. Wolff looked over once before blindly following and saw a small ledge about six feet down from the rim. She had already let herself down the ledge and now was hanging by her hands. She dropped again, this time to a much more narrow ledge. But it did not end; it ran at a forty-five degree angle down the face of the cliff. They could use it if they faced inward against the stone cliff-wall and moved sideways, their hands spread to gain friction against the wall.

Wolff used both hands also; he had stuck the horn through the belt.

There was a howl from above. He looked up to see the first of the gworl dropping onto the ledge. Then he glanced back at Chryseis and almost fell off from shock. She was gone.

Slowly, he turned his head to see over his shoulder and down below. He fully expected to find her falling down the face of the cliff, if not already past it and plunging into the green abyss.

"Wolff!" she said. Her head was sticking out from the cliff itself. "There's a cave here. Hurry."

Trembling, sweating, he inched along the ledge to her and presently was inside an opening. The ceiling of the cave was several feet higher than his head; he could almost touch the walls on both sides when he stretched out his arms; the interior ran into the darkness.

"How far back does it go?"

"Not very far. But there's a natural shaft, a fault in the rock, that leads down. It opens on the bottom of the world; there's nothing below, nothing but air and sky."

"This can't be," he said slowly. "But it is. A universe founded on physical principles completely different than those of my universe. A flat planet with edges. But I don't understand how gravity works here. Where is its center?"

She shrugged and said, "The Lord may have told me a long time ago. But I've forgotten. I'd even forgotten he told me that Earth was round."

Wolff took the leather belt off, slid the scabbards off it, and picked up an oval black rock weighing about ten pounds. He slipped the belt through the buckle and then placed the stone within the loop. After piercing a hole near the buckle with the point of his knife, he tightened the loop. He had only to buckle the belt, and he was armed with a thong at the end of which was a heavy stone.

"You get behind and to one side of me," he said. "If I miss any, if one gets in past me, you push while he's off-balance. But don't go over yourself. Do you think you can do it?"

She nodded her head but evidently did not trust herself to speak.

"This is asking a lot of you. I'd understand if you cracked up completely. But, basically, you're made of sturdy ancient-Hellenic stock. They were a pretty tough lot in those days; you can't have lost your strength, even in this deadening pseudo-Paradise."

"I wasn't Achaean," she said. "I was Sminthean. But you are, in a way, right. I don't feel as badly as I thought I would. Only..."

"Only it takes getting used to," he said. He was encouraged, for he had expected a different reaction. If she could keep it up, the two of them might make it through this. But if she fell apart and he had a hysterical woman to control, both might fall under the attack of the gworl.

"Speaking of which," he muttered as he saw black, hairy, gnarled fingers slide around the corner of the cave. He swung the belt hard so that the stone at its end smashed the hand. There was a bellow of surprise and pain, then a long ululating scream as the gworl fell. Wolff did not wait for the next one to appear. He got as close to the lip of the cave ledge as he dared and swung the stone again. It whipped around the corner and thudded against something soft. Another scream came, and it, too, faded away into the nothingness of the green sky.

"Three down, seven to go! Provided that no more have joined them."

He said to Chryseis, "They may not be able to get in here. But they can starve us out."

"The horn?"

He laughed. "They wouldn't let us go now even if I did hand them the horn. And I don't intend for them to get it. I'll throw the horn into the sky rather than do that."

A figure was silhouetted against the mouth of the cave as it dropped from above. The gworl, swinging in, landed on his feet and teetered for a second. But he threw himself forward, rolled in a hairy ball, and was up on his feet again. Wolff was so surprised that he failed to react immediately. He had not expected them to be able to climb above the cave and let themselves down, for the rock above the cave had looked smooth. Somehow, one had done it, and now he was inside, on his feet, a knife in hand.