twenty-five steps and he left the others behind. All except the bearded man. He neither paused nor looked back.

Johnson's stomach had drawn up into a tight knot now, and his head was beginning to feel light. There was a faint ringing in his ears.

By the time he reached the end of the guide rope, nausea was creeping up from his stomach and into his throat. This was as far as it was supposed to be safe to go; the advertising literature had it that here was the point of no return. Up ahead his quarry was walking half doubled over, weaving back and forth, as though he were intoxicated. But he did not pause.

Johnson turned to look back, and felt his breakfast fighting to come up. From his perspective, the ground and the spectators watching him had swung to a position almost perpendicular to him. He felt that he was about to slide off into space. A wave of vertigo swept over him, his legs folded and he fell to the ground—sicker than he had ever been before in his life. Now he knew why the man ahead never looked back.

For a moment Johnson wondered whether he should give up. But, even as he debated, tenacity pulled him to his feet and forced him on.

And now something new was added to his vast discomfort. Tiny twinges of pain, like small electric shocks, began shooting up his legs, increasing in intensity with each step he took. The pain built up until the rusty taste of blood in his mouth told him that he had bitten into the flesh of his lower lip.

Johnson's only consolation now was the thought that the man ahead of him must be suffering worse than he. At each step the pain increased its tempo, and the sound within his head grew to a battering roar. Although he felt himself at the last frayed ends of his vitality, he managed to stagger on.

Abruptly he realized that he had very nearly overtaken the man ahead. Through eyes glazed with pain, he saw the other, still standing, but swaying with agony and sickness. The man seemed to be gathering his resources for some supreme effort.

He tottered ahead two more steps, threw himself forward—and disappeared!

If he paused now, Johnson knew he would never be able to move again. Only will power and momentum carried him on. He stumbled and pitched forward. A searing pain traced a path through his head and he felt himself falling.

e was certain that he had never lost consciousness. The ground came up to meet him, and, with a last effort, he twisted his right shoulder inward. His cheek slid along the dirt and he lay on his side without strength. His legs pushed forward in a steady jerking movement as he fought to quiet his quivering muscles.

Gradually a soothing lethargy bathed Johnson's body. His pains vanished, and the sickness left his stomach.

But something was wrong—terribly wrong!

Slowly he climbed to his feet and stood looking about him. He was still on the narrow arm of the Strip. On either side of him banks of white clouds, with the consistency of thick smoke, billowed and curled about the Strip—but somehow they left its pathway clear.

Johnson shook his head. The wrongness, he guessed, was in his own mind. But he was unable to determine what it was. Desperately he marshalled his scattered thoughts. Nothing. He took one groping step in the direction from which he had come—and staggered back from a wall of pain as tangible as a concrete structure.

He had no choice except to go forward. There was something he must do, he realized, but what was it? With the question came the answer to what was troubling him.

His memory was gone!

Or, at least, a great gap had been torn through it as though carved out by a giant blade. Briefly, despair threatened to overwhelm him.

"Hold it!" Johnson spoke aloud, and the words sobered him.

All fears became worse when not looked at. He had to bring