Since then there had been a quarter century of casual contact, without even a face-to-face meeting during the last ten years. When she had been elected President, Celine had informed Wilmer of her new position. His congratulations were sincere, but puzzled. Anything resembling politics was far over his horizon.

Wilmer never was flustered, never overreacted, never became overexcited. So why had he arrived unannounced for a “most urgent” meeting, bringing with him a total stranger?

Unlike Wilmer, Celine was a world-class worrier. Part of her internal jitters was at the thought of seeing him again after so many years; but a larger part was her conviction that he brought bad news. The final meeting of the day, she was sure, was going to be more disturbing than all the others combined.

The call came in to Will Davis’s suit. He at once turned to John Hyslop, just a few feet away from him.

“This is for you, boyo.”

“Cusp Station local? If it is, it can wait until we’re finished.”

“Not this one. Urgent, from Sky City. They called me because they say your suit doesn’t answer.”

“Of course it doesn’t. I switched off so we could get some work done. But I can’t ignore it if it’s Sky City and urgent. Damnation. What do they say?”

“I don’t know. It’s personal, and it’s scrambled. We can’t go direct link. I’ll have to relay through Cusp Station control to your suit, so you can decode.”

It seemed ridiculous. The two men floated side by side, less than four feet from each other. They could have put their helmets together and talked without any radio link at all, but a scrambled message could not be transferred and interpreted that way. Also, from John Hyslop’s point of view the communication could hardly have come at a worse time. Sky City maintained mid-Atlantic, a clock zone convenient for workdays in America and Europe. So far as city workers were concerned, the call to John was made at eight in the morning — a reasonable time.

But the few humans and innumerable machines working on the space shield enjoyed no regular hours and no fixed clock. Schedules were defined by need, with always the same underlying message: Do this as fast as you can, and remember that it may not be fast enough.

The cat-sized rolfes, robotic brainchildren of Gordy Rolfe and his great contribution to the building of the space shield, could work twenty-four hours a day. But humans could not. So the call arrived when John Hyslop, Amanda Corrigan, Will Davis, Lauren Stansfield, Rico Ruggiero, and Jessie Kahn were at the tail end of a thirty-hour troubleshooting stint. John and Lauren were also at the tail end of their stamina. They had been up for seven hours before this effort began, tying up a meeting at Sky City before heading for Cusp Station. For the final ten work hours their awareness had been Neirling-boosted, so they would have to boost again soon, or crash. And when you crashed, you stayed out for a full sleep period. John had hoped to see this meeting to its end, then fade at once.

He switched to internal mode and listened to the message as it was unscrambled by his suit. “Dr. Colombo needs your presence as soon as possible on Sky City. We have a new problem.”

The voice was that of Goldy Jensen, Bruno Colombo’s personal assistant. Her tone — like her message — revealed nothing more with repeated hearings.

A new problem.

That might, please God, mean a technical difficulty. The John Hyslop job description, if anyone ever bothered to pull it up and read it, said he was chief engineer for the shield. In practice, he seemed to do whatever Bruno Colombo needed him to do, on Sky City and off it.

John switched back to external mode. Will Davis and Lauren Stansfield were uploading the proposed revision for the construction profile of one section of the space shield into the subsidiary computation network at Cusp Station while Jessie, Rico, and Amanda transferred the group recommendations to Torrance Harbish and the main network back on Sky City, where the real computing power resided. But they all had one eye on him. As soon as he clicked back to local circuits they stared at him expectantly.

“Everything all right?” Lauren asked. She was John’s number one assistant, a short, soft-spoken woman with auburn hair and big eyes. She dressed well and expensively, which together with her careful attention to her appearance made some of the engineers regard her as a lightweight. John knew better. He had learned to rely on Lauren in any emergency. She knew more about the interior layout of Sky City than anyone — John included — and her only hobby seemed to be roaming the space city’s thousands of corridors, checking the various life-support systems.

Now she was asking a question within a question. They had two more decisions to make before the meeting ended, and Lauren wanted to know if that would be possible.

There was no point in waiting, and no way to pull out gracefully.

“I’m sorry.” John spoke on open circuit. “Everything here is going well, and I think we’re pulling things back toward schedule. But I have to leave. I must return to Sky City.”

Jessie Kahn was young, new, naturally shy, and up from Earth only four months. She also had an intensity and an honesty that outweighed her natural reticence and, in John Hyslop’s view, pointed to a very bright future.

She said at once, “The questions of reduced shield efficiency and probable sensor losses must be addressed today. They can’t wait. And those issues require your personal involvement and approval.”

“I know.” John realized that he was going to shock her, but she had to learn sometime about the world of impossible deadlines. “I’ll fly back. You get in touch with me when your meeting finishes. Whatever you decide, I’ll approve it.”

He saw her face. He was feeling the pressure himself, and he was tempted to add, Don’t give me a hard time, Jessie. I’d hate to spoil your idealism, but I don’t have time for polite discussion. I have to boost again, because when I reach Sky City I have to be awake for whatever shit Bruno Colombo throws at me. And the thought of that second boost doesn’t thrill me at all.

His warning wasn’t necessary. Will Davis was a seasoned shield engineer who had spent only three days on Sky City in the past year — the opposite of Amanda, Lauren, and Rico, who left Sky City only when dragged out for emergency efforts like today’s. But Will was Jessie Kahn’s unofficial mentor, and he knew enough to step in and ask in his lilting Welsh, “What is it then, John Hyslop? A direct command? Might it be you’ve received marching orders from His Lordship?”

“You’ve got it.”

“What’s he want with you this time?”

“Do you think he’s going to tell me before I get there?”

“No, man. Not if he’s half the pain in the ass he used to be. I’m glad it’s you off to see him and not me.”

Everyone but Jessie laughed. They had suffered their own unpleasant experiences with Bruno Colombo. She, not sure how the conversation had suddenly veered away from her concerns, looked from one person to the other but said nothing.

John decided that there was no point in further discussion. The others could give whatever additional explanations they liked. “I’m going to do a second boost, Lauren,” he said. “Right now. You don’t need to do that, so make sure you get somewhere safe before you crash.

Will, you’ll have to wrap it up here in an hour or two. Make sure the rolfes are reassigned to the shield when you’re done with them.”

Their meeting was taking place in hard vacuum. John headed straight for the station exit, switched to suit channel as soon as he was outside, and said, “Take me to Sky City. Use a continuous one-gee thrust trajectory, and provide a zero relative velocity on arrival.”