He just hoped no one on the other side was in a position to see him.

“Katherine! Come on!” He gently began tearing the wall upward like fabric. It was tough, but it gave. When he looked up, she hadn’t moved. “Come on-” He lowered his voice, suddenly aware that he had a sizable opening in the wall, nearly enough to crawl through…or be heard through.

Katherine turned and started walking away.

Derec wanted to shout, but didn’t dare. Then, clenching his jaw, he crawled into the opening, leaving his boot behind to hold the breach as the wall grew together again behind him. He would have a talk with her later.

He found himself on the floor behind a large, bulky piece of machinery. The sounds of robots moving about reached him, but most would be function robots. He did not hear any voices. Of course, the foremen had their comlinks for communication with each other.

He spotted Security 1K sitting high on a stool at the far side of the dome, monitoring a console that probably reported a number of effects that would include the vibrations in the wall that Derec and Katherine had caused by touching and punching it. Since IK was still at the console, Derec judged that the monitor had accepted the boot as part of the wall. Certainly, the wall had grown in solidly around it.

A ceiling was just over the security console, signifying at least one upper floor, if not more. The interior curve of the dome was out of sight above it. On the floor, the entire crew of robots assigned to Keymo seemed to be working on different pieces of equipment that varied greatly in size. One foreman was seated at a computer console on the floor beneath the raised seat of Security 1K. Derec guessed that this was Keymo, and started working his way through the machines to reach the robot without being noticed.

Derec knew that he would not have much time. Even as he crawled over cables on the floor and between different machine housings, he wondered if he should just stand up, run over to Keymo and start talking right away. As it was, Security 1K might become alerted to his presence and throw him out before he could start his pitch.

He stopped to get his bearings. Keymo was much closer now, studying the readings on the console. It looked like a good time to approach the robot.

Security 1K had not moved.

If Katherine had come in with him, one of them could have provided a diversion while the other spoke to Keymo. But it was too late for that now. He took another deep breath and stood up.

He felt totally exposed and vulnerable as he walked across the floor, but his presence caused no noticeable stir among the robots. When he reached Keymo’s desk, the chief robot of the facility looked up.

“I require the Key to Perihelion,” Derec said formally. He edged to the side of the console and peeked at the readouts.

“You would be the human Derec,” said Keymo. “Giving you the Key is not possible.”

“We must get off the planet in order to survive. The Key is our only means of transportation.”

“What is the danger to you and your companion on this planet?”

“Well, we just aren’t supposed to live on a planet of robots. We need the company of other humans. Uh…” He knew this line of debate was weak, but it was all he had. The exact nature of Katherine’s chronic condition was unknown to him, and therefore too vague to use.

“That is not a danger by itself.”

“That’s what I told him,” said a voice behind Derec.

He tried to turn, but felt firm hands under his arms that lifted him off his feet. It was Security 1K, of course, and Derec did not bother to protest as he was carted to the wall like a lump of waste matter. He could not see how the robot opened a new slit in the wall, but he noted that the boot was elsewhere, and apparently still unnoticed. It would provide another opportunity later.

He was deposited gently but unceremoniously outside the wall, where he stood awkwardly on one booted foot. Behind him, the wall grew together. Katherine walked slowly toward him and stopped.

“I could have used you in there,” he growled.

“I didn’t realize you’d get in. Then I didn’t know what to do.” She stared at the ground in front of her.

“Let’s get out of here.”

Derec was in no mood for another crazy ride in the vacuum chute, and he didn’t want to talk to her until they were in private. He hitched rides for them on the top of an enclosed transport vehicle, and on the exterior ladders of a vehicle the purpose of which Derec could not divine. As long as the robot drivers judged their human passengers to be riding safely, they had no objection. Katherine was withdrawn all the way home, and he left her alone.

When they had returned, he went right back to the console. She reluctantly stood behind him with her arms folded. He kept his mind on his work with an effort.

“Did you learn anything while you were inside?” she asked quietly.

“A little,” he said coldly. “It might amount to something and it might not. I read an entry number on Keymo’s console, and I’m running it through the central computer.”

“Are you sure it’s really the Key Center?”

“Don’t you remember? We demanded to see Keymo, and the security robot didn’t deny he was in there. I demanded the Key from the top robot, and he didn’t deny having it.”

“Okay, okay.”

He paused to study the information that had come up. She came closer to read over his shoulder.

“It’s a list of substances, mostly metals and synthetics. Percentages of each one…energy consumption in the dome.”

“Look on the right,” said Katherine. “That’s the designation for hyperspace. It’s an experiment of some kind, consuming air.”

“Air-the chutes! The vacuum chutes. That’s why they’re using such an old technology. What did that construction robot say? The vacuum is a side effect of something else going on. This is it.”

“But what is it?” She asked cautiously.

He started an angry retort, then decided to have it out with her after he had finished considering this information. In the long run, it was more important. “I’m taking another look at that supply requisition we saw earlier. All the same substances are listed, in the same percentages. I wonder…”

“They’re duplicating the Key.”

“You think so?”

“I’m sure of it, Derec. And, look at the addendum on the supply requisition. They added small amounts there at the dome.”

“That would be the original Key,” Derec said slowly. “They…had to break it down to analyze it. Then they tossed the pieces into the pool of materials. It’s gone.”

“But they’re making more. Derec, this will make it easier for us to get one. Instead of one Key under careful guard, they’ll have a bunch of them we can try for.”

“I just hope Keymo is duplicating them accurately. And we might have to wait for them to turn out a few. We can’t get something that hasn’t been made yet.”

“Uh, Derec? Would you turn around?”

He turned in his chair and looked up at her.

“I guess you deserve an explanation. I know I’ve been acting weird. And I’m sorry I didn’t go inside with you. I had my mind on something else at the wrong time.”

“The wrong time!” Derec leaped out of his chair, glad to have the opening. “The worst possible time! We might have gotten the Key-or a key, anyway!”

“Derec, please. I’m trying to explain. Anyway, maybe there weren’t any to get, like you said.”

“All right! All right. Go ahead and explain.” He paced away from her and turned at the wall. “Go ahead.”

“Derec, I know who designed Robot City. And why.”

“ What?”

“I-”

“Why didn’t you tell me?” He raged. “No! Never mind that -who did build this place?” His astonishment and curiosity were interfering with his anger.

“Before I get to that, my real name is Ariel Welsh.”