In the row in front sat Mulligan Johnson, the top mirror-matter specialist for Photonics. John Hyslop had spoken of problems with the latest group of mirror-matter thrustors, and those were Photonics’s responsibility. Mulligan was here to troubleshoot, stir the Photonics’s staff to greater efforts, and smooth ruffled client feathers.

The other two faces presented more of a mystery. Candy Wentzel, sitting next to Mulligan Johnson, was a top media reporter. She might be doing some kind of feature article on the shield and its schedule problems, but that wasn’t her usual line. She was a muckraker, chasing scandals at the highest levels of government and industry. A schedule delay might lead to a world-crippling disaster, but it still wasn’t a scandal. To justify Candy’s highly expensive and decorative presence, Bruno Colombo himself would have to turn out to be the Sky City murderer.

Maddy smiled inwardly at the idea — Goldy Jensen would have to be in on it, too, because Colombo’s personal assistant tracked his movements every waking (and sleeping) second. And there was the question of motive. Bruno had none. He might kill, but only for promotion or political preferment.

Maddy turned her attention to the fourth figure. Familiar, yes, but in what context? She couldn’t be absolutely sure, but she thought she had seen him around the offices of the Argos Group. He was of medium height and strong build, with a sallow complexion and dark, short-cut hair; it was the sort of nondescript face and figure you would never notice in a crowd, unless those eyes fixed on you as they had fixed on Maddy before takeoff.

They were a tawny brown in color, too light for that dark face, and they moved constantly to scan everything around him. If she suspected that she thought she knew him, she felt quite certain that he knew her. For the past half hour he had been holding on his knees a black cylindrical bag about eighteen inches long and eight inches across. She could see a piece of pink and mauve cloth sticking out of the end of it. The bag had been stowed away during takeoff, so why was he nursing it now? You did that only when you were carrying something precious, something that you were afraid you might lose.

She glanced again to John Hyslop, still sitting in silence at her side. Was she going to have to work with a zombie? He hadn’t taken out anything to read, he didn’t have a headset, he hadn’t said a word. He was holding a tiny notepad in his hand, and now and again he scribbled a couple of digits. He seemed totally unaware of her presence, and she wasn’t used to being ignored. She expected male attention. He wasn’t gay; her own instincts told her that as well as the background briefing documents. But he seemed lost in another world, one where Maddy Wheatstone did not exist.

Her musings ended when the docking phase began and the usual string of visuals appeared on the seat displays. They showed dozens of locations on Sky City and told what the visitor might do at each one. They amounted to commercials that could not be turned off, and they were boring even the first time you heard them. When you had been shuttle-hopping as Maddy had for the past week and a half, in a constant dizzy veering between Earth and Sky, you wanted to find the owner of that soft, persuasive voice and strangle him.

That led to another thought: The person who had taken those shots had been everywhere in Sky City and must know it in detail. Wouldn’t he be in a perfect position to travel around and kill without being noticed?

Maddy dismissed the thought as soon as she had it. It was an idea that security had surely explored and dismissed. Other people’s jobs always seemed easier than yours until you actually had to do them.

The visuals ended as a vibration along the shuttle’s outer hull indicated that an umbilical was being clamped into position. The shuttle docking was taking place at an air-match port, and the air pressure and gas mix inside the shuttle had slowly been adjusted after takeoff from Earth standard to Sky City normal. The passengers would be able to leave without the use of suits or masks.

John Hyslop showed no sign of moving. He was still writing numbers on his notepad. Maddy watched as the shuttle hatch opened and the LMB executive at once hurried away. His every movement said Time is money!

Mulligan Johnson and Candy Wentzel were next. He was talking animatedly and Candy was smiling and nodding.

Some scandal involving Photonics?

Hard to imagine. Much more likely, Candy was a newcomer and needed somebody who knew his way around Sky City. In media races, an hour’s delay could be fatal. Maddy knew what she would have done, and Candy had probably followed the same line of logic: examined the passenger list, decided in real time that Mulligan Johnson was her best bet, and collected him as effortlessly as a child picking a daisy. Maddy didn’t disapprove of that. Candy, like Maddy, took her job seriously. You did what you had to do.

Next, the familiar-but-unfamiliar dark-faced stranger vanished through the hatch, still clutching his black cylindrical bag. The only passengers left were two who had arrived on the shuttle in wheelchairs and who were now waiting for nursing assistance. Both men had the puffy complexion and purplish lips suggesting congestive heart disease. The low-gee environment of Sky City might help — if they survived the shock of the launch and the strain of vomiting in the first few days. Space was the last resort for those individuals who, incomprehensibly to Maddy, refused a simple heart-lung replacement.

Still John Hyslop was sitting and staring at nothing. Maddy reached the end of her patience and nudged him. “Don’t we have meetings to attend?”

He turned to look at her with those steady gray eyes. “We’ll be there on time.”

She knew now that his jumpiness at their first meeting had been the result of a Neirling boost. Usually he was the calmest man she had ever met — calm enough to drive her crazy.

“Not if we hang around here, we won’t.” Maddy stood up. “Let’s go.”

He nodded, stood up also, and started toward the hatch. But when he came to it he didn’t go through. Instead he continued forward.

“Where—” Maddy began, and paused. A strange sensation of dizziness hit her as she left her seat. It passed as quickly as it had come, but by that time John had drifted all the way to the end of the main compartment and through the door into the pilot’s cabin. Passengers were not supposed to go in there.

“Quite a difference,” he was saying as Maddy came up behind him. “Fifteen percent?”

“At least.” The woman in the pilot’s seat was lean and blond and hollow-cheeked. She turned to survey Maddy with eyes of arctic blue, then nodded to indicate that she, too, was included in the conversation. “The end spec is supposed to be a twenty-one percent increase for the new engines, but we’ve not quite reached that yet.”

“That will be great. What’s the change in final mass ratio?”

“A factor of two with present performance. Over three if we ever hit spec.”

“I have a thought about that. How long will you be here?”

“Nine hours. Then we head back down.”

“Good. Plenty of time.” Hyslop again had the little notebook in his hand. “I was listening closely right through the powered ascent phase, and it sounded to me as though one cluster wasn’t firing as cleanly as the others.”

“Exactly right.”

“L-8?”

“That’s the way I feel it, and it’s the way the gyros measure it. But we’ve been through ground maintenance twice, and they insist that everything is nominal.”

“I bet your tests were done at constant external pressure. Downside maintenance sometimes cuts corners that way and uses ambient. I think the aerospike for the L-8 cluster may be following a recorded pressure that’s trailing the actual pressure by a few seconds. Don’t ask me why, because I don’t know. But if you call Dan Iverson at the Flight Test Facility here on Sky City, the FTF can run you a dynamic test with variable ambient air pressures. You’ll be able to find out if that’s the reason the L-8 cluster is off.”