"After you've found I'm innocent, you would do well to kill me! If you don't, I'll kill you! I speak the truth!"

"We'll see."

Burton planned, if the Sumerian was not X, to install a posthypnotic command that Gilgamesh forgive him when he came out of the trance. He would have ordered him to forget the injury, but the others would no doubt remind him of it.

"Place your hands on the back of your neck," Burton said. "Then turn around. Don't worry about being hurt too much. I know precisely just how much force I'll need. You won't be unconscious for more than a few seconds."

Burton reversed the pistol and lifted it by its butt. Gilgamesh, bellowing, "No!" whirled, his arms flying out from his neck, and his hand struck the pistol and tore it from Burton's grip-Alice should have fired then. Instead, she tried to beat the Sumerian on the back with her pistol barrel. Burton was very strong, but he went down under the herculean power of Gilgamesh and then was lifted up. He struck Gilgamesh in the face, making his nose bleed and bruising the skin. The Sumerian lifted him above his head and threw him against the wall. Stunned, Burton dropped to the floor.

The others were shouting and screaming, and Alice was yelling. But she managed to bring the butt of her weapon, now reversed, down on the head of Gilgamesh. He swayed, then began to crumple.

Ah Qaaq, swift despite his fat, ran by Alice, snatching the pistol from her hand, and continued toward the end of the corridor.

Though dazed, Burton struggled to get up, shouting, "Get him! Get him! He's the Ethical! X! X!"

His legs felt as if they were balloons out of which the air was whistling. He slid back down against the wall.

The Mayan—no, no Mayan he—slammed his palm against the wall on his left. Immediately, the door at the end of the corridor slid into a recess in the wall.

Burton tried to note the exact location of the area that X had struck. The blow had undoubtedly activated machinery behind the wall. And since it opened the door, it also was inhibited from releasing whatever it was that had felled the Egyptians.

Nur, a small skinny dark flash, scooped up a pistol as he ran by the pile. Then he stopped, and he lifted the heavy weapon in both hands. The gun boomed. The projectile struck the side of the door as X went around it. Pieces of plastic flew through the exit and against the wall opposite. X fell, though only his black-clothed legs showed for a moment. Then they were gone.

Nur ran after him but stopped at the doorway. He leaned out cautiously, and at once jerked his head back. The bullet fired by X smashed itself against the wall just outside the door. Nur got down on his knees and looked around the exit again. Another boom. Nur seemed uninjured.

By then the others had picked up their weapons and were running toward the doorway. <

Though regrets were useless, Burton regretted that he had not chosen Ah Qaaq first for hypnotism.

He called to Alice, who was bending over Gilgamesh, to help him up. Weeping she came to him and pulled up on his wrists. His head was clearing, and his legs seemed steadier. He'd be all right in another minute.

He called, "Frigate! Tai-Peng! Turpin! Get Gilgamesh out of here! Everybody else! Out! Out before he closes the door!"

Nur yelled, "He's gone now!"

The three men came running, and they picked the Sumerian' s heavy body and bore it toward the doorway. Burton leaned on Alice, his arm around her neck, and they followed the others. By the time he got to the exit, he felt recovered enough to tell Alice that he could go it by himself.

Turpin placed his grail in the doorway so the door couldn't be fully closed. Just as Alice and Burton stepped into the corridor, the door shot back out of its recess, slammed into the grail, and stopped.

Nur indicated the blood on the floor by the doorway and the red spots farther along.

"The bullet smashed against the wall, but some of the fragments got him."

The corridor ran both ways as far as they could see. It was illuminated by the shadowless light and was forty feet wide and fifty high by eye estimate. It gently curved to follow the roundness of the exterior. Burton wondered what was between the outer wall of the corridor and the outer wall of the tower. Probably, some of it was empty, but other spaces might contain machinery of some sort or storage facilities. At irregular intervals, at his eye level, the walls held bas-relief letters or symbols some of which superficially resembled runes and others Hindustani characters.

Burton left a bullet by the wall to mark the entrance if the door should somehow close.

Shortly after the bloodstains ceased, the trackers came across a bay in the center of which was a circular hole about a hundred feet across. Burton stood on the edge and looked down. Lights streamed out along the black shaft from many levels, other bays or rooms. He didn't know how deep the shaft went, but he guessed that it was miles. When he got down on his knees, his hands gripping the edge, and looked up, he saw the same thing. However, the shaft could go up no more than a mile, the height of the tower from sea level.

By then Gilgamesh was recovering. He sat on the floor holding his head and groaning. After a minute, he looked up.

"What happened?"

Burton told him. The Sumerian moaned, then said, "And you didn't strike me? It was the woman?"

"Yes, I apologize, if it will do any good. But I had to know."

"She was only fighting to save her man. And since you did not hit me, there is no insult. Though there is plenty of injury."

"I think you'll be all right," Burton said.

He forebore to say that he had hit Gilgamesh in the face. Truth could be sacrificed in this situation. He'd gone through his life making enemies because he didn't care if he did and even got a certain satisfaction from it. But during the past twenty years he'd seen that he was behaving irrationally in this respect. Nur, the Sufi, had taught him that, though not directly. Burton had learned while listening to Nur's conversations with his disciple Frigate.

"I think," Burton said, "that X took a lift of some sort. I don't see any, though. Nor do I see any controls to bring one up or down to here."

"Maybe that's because there isn't any cage," Frigate said.

Burton stared at him.

Frigate took a plastic bullet out of the bag that hung from his belt. He threw it twenty feet into the emptiness. It stopped as if it were in jelly at the level of the floor.

"Well, I'll be damned! I didn't think it was so, but it is!"

"What is?"

"There's some kind of field in the shaft. So... how do you go where you want to? Maybe the field moves you according to a codeword."

"That is good thinking," Nur said.

"Thank you, master. Only... if one person wants to go down at the same time another wants to go up... ? Maybe the field can do both simultaneously."

If the shafts—there must be others—were the only way to get from one floor to another, they were trapped. All the Ethical had to do was to let them starve.

Burton became angry. All his life he'd felt caged and he had broken out of some of the cages, though the big ones had restrained him. Now he was on the verge of solving this great mystery, and he was trapped again. This one, he might not escape from.

He stepped out into openness, putting one foot down slowly until he felt resistance. When he'd determined that his weight was going to be held, he moved entirely into the shaft. He was near panic; anybody unfamiliar with the setup would be. But here he was, standing on nothing, apparently, and an abyss below him.

He stopped, picked up the bullet, and threw it to Frigate.

"Now what?" Nur said.

Burton looked up and then down.

"I don't know. It's not just like being in air only. There's a slight resistance to my movements. I don't have any trouble breathing, however."