"Saw him where?" the security man asked, his interest instantly intensified.

"I can't be sure, but it seems to me that he was shopping in the mall last week when I was there. Come to think of it, he was having dinner atBrindisi 's with another man the night before last. I remember because I caught them looking at me a couple of times. I thought one of them was trying to work up his courage to try to pick me up."

"There was another one, you say?"

"Yes, I'm certain of it."

The security agent reached for his comm unit and ordered the spaceport sealed off. Meanwhile, the agents who had been clustered around the body took out their weapons and moved to take up station along the length of the concourse. Sands and Kimber were ignored for five minutes while the security people made their arrangements. Finally, the agent in command returned. "Let's go."

"Go where?"

"Somewhere we can be sure you will be safe.

They were marched through a side door into a corridor that was deserted except for their security entourage. Ten minutes later, they were in Kimber's apartment with guards three deep beyond the door.

"Damn it, I ought to resign!" Arvin Taggart growled. The Titanian security chief paced Kimber's livingroom like a caged lion. Lars had never seen a lion except in photographs. Nor had anyone else, for that matter. Still, the expression lived on in the language and now he knew precisely what it meant. There was something about Taggart's mood that suggested a coiled spring about to be released.

"Take it easy," Envon Crawford advised. The factor and his security man had arrived together. After Crawford made sure his daughter was all right, he had turned suddenly professional. The loving parent was gone, replaced by the iron willed chief executive whose territory had been violated. Like Taggart, Crawford was in a murderous mood and working hard to control it. "Your people handled it as well as we could expect. Both of their charges are safe. That's what counts."

"No, sir, it isn't! Damn it, this assassin should never have gotten past our cordon. The fact that shots were fired at all means we failed. You don't live long in this business depending on dumb luck, which is precisely what saved us today!"

"I don't understand something," Kimber said. Like Sands, she had had an hour to calm down. "They had Halley helpless in Lars's apartment last month. Why didn't they kill her then? More to the point, if they spared her life then, why try to kill us now?"

"It wasn't the same man," Taggart said through clenched teeth. "We found identification on the body identifying him as a chemical salesman from Borodin in the North Equatorial Belt. He arrived aboard the Julia Havler only two weeks ago. He wasn't on Titan when Halley was attacked."

"Another Alliance agent?"

"Possibly the agent who knocked Halley out wasn't from the Alliance. There may be other players in the game that we don't know about."

"Another Alliance faction, perhaps?" Crawford asked.

"Possible," Taggart agreed. "We've been working our source at the Cloudcroft museum overtime. It seems Captain Sands's raid put more of a strain on the council than we recognized at the time. This assassin could be a response by either the Accretionists or Militarists."

"Are we sure he was a professional?"

Taggart frowned. "You told my men that he looked like one."

Sands shrugged. "At the time, I thought so. However, I have been thinking about it. Surely a professional would have been a better shot."

"He wasn't as bad as you might think," Taggart replied. "You have to consider the handicaps under which he was working."

"What handicaps?"

"The gravity for one. He was a Saturnian, used to one plus standard gees of acceleration. People from Saturn tend to aim high in low gravity. From Kimber's testimony, it is obvious that your appearance surprised him. Probably, he was trailing her and had no idea she was going out to the spaceport to meet you. When he saw you, there was that single moment he let himself react. Kimber saw his unguarded reaction and recognized it for what it was, giving him no choice but to open fire.

"Yet, even though he was under pressure and firing in one-sixth his normal gravity, he was able to put rounds within a few centimeters of your head. He was undoubtedly concentrating so much on compensating for the lighter-than-normal gravity field that he forgot one other crucial point.""What was that?"

"The spaceport concourse is on the outer ring of Main Dome. Subconsciously, he probably thought it was a straight corridor. That threw off his aim. Basically, his brain misprocessed the visual cues and so placed him in the wrong place for firing at you."

"You mean he suffered an optical illusion?" Kimber asked.

"Something like that," Taggart agreed. "I've got the behavioral psychologists looking into the situation.

They'll tell us if there's anything to the theory."

"At least he's dead," Kimber said. "We're safe for the time being."

"I'm not sure of that at all. "We ranHavler 's passenger list through the computer. We are attempting to locate the other passengers now. We have not had a lot of time to check, but we think one other is missing -- a man matching the description of the man you saw inBrindisi 's the other evening. The two of them were probably a team."

"We've got to catch him!" Envon Crawford yelled.

"We're trying, sir. However, he has undoubtedly heard about the shootout at the spaceport by now. If he is truly a professional, he will have prepared any number of contingency plans. He's probably changed his looks and gone to ground somewhere we'll not expect him."

"What you are saying, Arvin, is that my daughter and Lars are still in danger?"

"We've doubled up on security, Factor. If they will agree to stay hidden until we've found this second agent, they ought to be reasonably safe."

The factor shook his head. "Reasonably safe until the Alliance can send someone else! Remember, we have got at least one other agent loose in Titania. How many others are there? Two, three, a dozen?"

Taggart shrugged elaborately. "What else can we do? If Kelt Dalishaar's people can reach them here, there is certainly no cloud city where they can take refuge. I suppose we could lock them up at the bottom of one of our deepest mine shafts. Even there, someone might bribe a member of the security force. There is no complete safety."

Crawford frowned. He was obviously wrestling with some decision. Finally, he sighed and turned to his daughter. "You're going to have to go away for awhile."

"Go where?" she asked. "You heard Arvin. If the Alliance is truly after us, they can reach us anywhere we go."

"Notanywhere ! There is one place where you will be beyond their reach. While you're gone, we can work at resolving this situation."

Confusion showed in Kimber's expression. "Where are you sending me, father?"

"Vixenleaves tomorrow. You and Lars will be aboard when she leaves. You're going to Earth!"

Chapter 21: Alliance.

Admiral Mikal Blount of the Alliance Navy sat in the cockpit of the fast prowler and scanned the whole vast blue-white expanse of sky before him. In the near distance to port, a seemingly infinite cloud wall marched slowly astern; while to starboard, the great trough of the North Temperate Belt stretched endlessly into haze. Even in the pristine air, the immense cloud canyon was too wide for Blount to have any hope of seeing the other side. The prowler's pilot also searched the sky. His younger eyes proved their worth when he reached out a black clad arm and pointed to the right of the aircraft's needle shaped prow.

"There, sir! Home."

Blount strained his eyes to their limit and was rewarded after a few seconds by the appearance of a single, silver bubble in the azure haze. The cloud city danced at the limits of vision for long seconds, and then seemed to split in two. In fact, another city had come into view. In quick succession, two cities became five, then five became ten. Suddenly, there were more cities in sight than were easy to tally at a glance. Yet, they continued to multiply as the prowler closed the distance. Despite the cluster's numbers, its individual cities were still minuscule when compared to the vast cloudscape that engulfed them. They looked like a string of tiny pearls lost in the folds of a giant's bedding.

The sudden reminder of just how puny were humanity's biggest constructs did nothing to bolster Blount's confidence. His composure had already been badly shaken by the message he had received at his headquarters aboard Glasgow. The coded dispatch had read simply:"Return immediately. Samorset ."

His first thought had been that Dalishaar had discovered the Navy's complicity in the raid on Cloudcroft.

After a few panic-stricken moments, he had reasoned that such an outcome was unlikely. Had the military's part in the raid become known, the summons would have come from Admiral Samorset's replacement. Indeed, it would likely not have come at all. The first Blount would hear of it would be when his own security chief arrived to arrest him.

Convinced that his precarious secret was still safe, Blount had run through the other possibilities. One distinct prospect was that Admiral Samorset feared exposure and was taking action to cover his tracks.

If so, the summons could well be Blount's death warrant. He alone knew the full details of the grand admiral's involvement, and would make a most damning witness should the case ever come before the council.

Blount had considered refusing the return order and using Glasgow's unsettled condition as an excuse.

He had rejected the idea out of hand. He had only his suspicions, and should they prove wrong, he would be destroying his career. The only way to find out what the admiral wanted was to face him directly. It had been with more than a little trepidation that Blount had ordered a fast ship to take him to Cloudcroft. It had taken six hours at top speed to reach the Alliance. The waiting was nearly over.

"Approach control is challenging us," the copilot reported.

"Answer them," Blount replied. He was aware that his presence in the cockpit made the two young officers nervous. He could not help that. If this were to be his last journey, he wanted it to be a memorable one. There are few sights as grand as watching Saturn's ever changing cloudscape unfold through a cockpit windscreen.

The two pilots banked their aircraft several times in response to directions from the city controllers.

Blount could not help letting a thin, humorless smile mark his lips as he watched them. This, too, was in response to his handiwork. Ever since the raid, the Navy was patrolling out to a radius of a thousand kilometers. Once a ship got in close, traffic control was rigid and unyielding, with city lasers focused continuously on everything within range.Ten minutes later, the admiral found himself among the giant balloons into which humanity had packed a few cubic kilometers of Earthlike environment. Blount never got over how fragile cloud cities looked when viewed from a moderate distance. Closer in it was easy to be overwhelmed by their sheer volume, but out here, their true fragility was all too apparent.

Cloud cities were the most delicate flying machines ever built by man. Even the strongest would quickly break up if it entered the storms that roiled vast portions of Saturn's atmosphere. Only in the clear rivers of air that marked the descending legs of convection cells, or the interiors of cyclones, could the delicate balloons survive. Even then, constant vigilance was required to avoid the turbulence and wind shears that dotted the major flyways.

"We have landing clearance," the pilot announced over his shoulder.

The prowler arrowed at one city that looked much like the others. Except this one, Blount knew, was the only city on Saturn that really counted. Government tower was clearly visible as they spiraled down toward the military landing bay that was their destination. As they drew even with the top of the Cloudcroft gasbag, Blount's eyes were drawn to the instrument package that belatedly scanned the skies for free-flying raiders. That, too, was a product of his handiwork.

As the prowler slowed to a hover and was then winched aboard, Mikal Blount was struck by the realization that the waiting was over. He would soon know what fate awaited him.

Naval Headquarters was not like Government Tower, perched ostentatiously atop the city deck.

Headquarters was located deep inside the support truss, a cubical fortress suspended from the open framework that was the backbone of the city. It was physically separated from the other truss spaces, with only a few tubeways providing access. Headquarters contained the main switching station through which electrical power from the fusion generator was delivered to the rest of the city. Its location made it nearly impregnable. Whether invading enemy or rampaging mob, no one would put the nerve center of the Alliance Navy out of action by anything less than the total destruction of the city.

Blount marched through the gently swaying length of access tube that bridged the gap between the military landing bay and headquarters. Daylight flooded upward through the walls of the transparent tube, highlighting the complex forest of braces that formed the interior of the support truss. He could sense through the soles of his boots the deep thrumming noise of the nearby city engines as they strove to keep Cloudcroft in the most favorable wind currents. The open gridwork of the tube floor allowed him to see the hanging black mass of the fusion generator. The generator's tiny size belied its great mass and volume. The generator served as the counterweight that kept the city upright.

The access tube was uncomfortably warm as the heated hydrogen rose around it to buoy the city. Blount knew that beyond the thin layer of plastic of the tubeway, the atmosphere was devoid of oxygen. Only the hydrogen-helium mix of Saturn's atmosphere was present. Like all enclosed spaces within the support truss, headquarters was sealed and pressurized. Only on the city's upper deck, beneath the habitat barrier, was there any illusion that human beings could breath the Saturnian atmosphere.

Blount came to the end of the long tube and crossed through an open hydrogen lock into a heavily armored entry chamber. There he found himself under the watchful eyes of a dozen security personnel.

He presented his credentials and stepped up to an instrument with a binocular eyepiece. He stared at the red dot that seemed to hang in space inside the machine. Somewhere deep inside headquarters, a computer compared the pattern of his retinas with those on file and found them the same. It sounded a beep and displayed a message visible only to the young lieutenant who was serving as Officer of theDeck. Blount watched the boy's reaction carefully for some clue as to the reception he would receive.

There was nothing to indicate that this was anything but routine. The lieutenant handed Blount's identity card back to him and saluted smartly.

"The grand admiral will see you immediately, sir. Do you wish an escort?"

Blount smiled in what he hoped was a nonchalant manner. "No need, son! I was walking these decks when you were still in diapers."

Somewhat relieved, Blount marched out of the entry chamber and toward the grand admiral's sanctum sanctorum. As he walked, his spirits were buoyed by the familiar sounds and activity around him. Here lay the Alliance's destiny. If Cloudcroft were to be the capital of Saturn one day, the men and women in his vast fortified cube would make it so.

He reached the grand admiral's office and was ushered inside after another check of his identity. Admiral Samorset glanced up from his workscreen as Blount saluted. The scowl on his face told Blount all he needed to know about his superior's mood.

"Your two assassins missed, Mikal!"

"Beg your pardon, sir."

"You heard me. The two fumble fingered idiots you assigned to kill Larson Sands have bungled the job!

One of them was killed outright and the other either has been captured or has gone into hiding. That is not the worst of it. The quarry has also fled."

"Fled where, sir?"

"To Earth, by all the furies!"

Blount blinked in surprise. In all his imaginings of what was behind Samorset's summons, this possibility had never occurred to him. It was galling enough to learn that his two handpicked men had failed, but to hear it from the grand admiral himself was especially irksome. He wondered where his superior was getting his information.

"Please, sir. Start at the beginning. What happened?"

As Samorset explained, a pattern became clear. Hardwick and Quintana had reached Titan without incident. They had spent two weeks locating and studying their targets. Halley Trevanon and Kimber Crawford had been easy to spot, but Larson Sands had proved more elusive. Apparently, he had been off Titan on some mission, a fact that had become obvious when Hardwick, trailing Kimber Crawford, had come upon him in the Titania spaceport. What had happened next was far from clear. Hardwick had been killed while trying to shoot Larson Sands and no one had heard from Airman Quintana in nearly thirty hours.

"How do you know all of this?" Blount asked finally.

"That's the worst part," the grand admiral replied with a growl. "I was called into the first councilor's office just before second sunset yesterday. He briefed me in detail."

"Dalishaar knows we sent assassins to Titan?"

The grand admiral shook his head. "He has his own agent in Titania. That agent reported the attempt to kill Sands. He could hardly have missed it. The Titanians are broadcasting it to anyone who will listen. Ido not think Dalishaar has connected the assassins with the Navy yet. Of course, he would hardly say so if he had. He had pictures of the dead man. I was able to recognize Hardwick from his service photo."

"Can anyone else do the same?"

Samorset shook his head. "The record has been expunged."

"And this other report? The one that has Sands fleeing to Earth. Does that come from the same agent?"

"It does. The agent reports seeing Sands, his female accomplice, and the Crawford woman all board a ship yesterday. The vessel's destination was not publicized, but some of the equipment convinced the first councilor that they are bound for Earth. I did some checking. Thereis a spacecraft out of Titania for Earth. Its time of launch corresponds to that reported by the agent."

"Did the first councilor also check the shipping records?"

Samorset shook his head. "The ship's destination wasn't posted at the time of our meeting."

"Then how did he know its destination?"

"A good question. A better one is how we are going to silence Sands. Earth is as far beyond our reach as it is possible to get."

"Not necessarily," Blount replied. "The Cloudcroft museum has been organizing an expedition for months. Perhaps we could use that to get at them."

The grand admiral sighed. "Not possible, I'm afraid. The officer in charge of the expedition is unreliable. I know him to be one of Dalishaar's stooges. I'd have him drummed out of the service if he weren't such a useful conduit for false information."

"All the more reason to replace him."