The mass driver was four meters long, built atop a pair of sturdy tables bolted together. It was nothing more than a pair of long straight parallel guides, each horseshoe-shaped in cross-section, the prongs of the horseshoes pointed toward each other with a narrow gap in between. The bucket, which would carry the payload, was lozenge-shaped in cross-section and almost filled the oval tunnel created by the two guides. Most of the bucket was empty payload space, but its outer jacket was of a special alloy supercooled by liquid helium so that it became a perfect superconducting electromagnet. This feature, combined with a force field generated in the two rails, suspended the bucket on a frictionless magnetic cushion. Electromagnets in the rails, artfully wound by Virgil, provided the acceleration, "kicking" the bucket and its contents from one end of the mass driver to the other.

Casimir relaxed visibly as he began pointing out the technical details. With long metal tongs he reached into a giant thermos flask and pulled out the supercold bucket, which was about the size of two beer cans side by side. He slid it into the breech of the mass driver. As it began to soak up warmth from the room, a cascade of frigid white helium poured from a vent on its back and spilled to the floor.

Krupp stood close by and asked questions. "What's the weight of the slug?"

"This," said Casimir, picking up a solid brass cylinder from the table, "is a one-kilogram mass. That's pretty small, but— " "No, it isn't." Krupp looked over at his friend, who raised his eyebrows and nodded. "Nothing small about it."

Casimir smiled weakly and nodded in thanks. Krupp continued, "What's the muzzle velocity?"

Here Casimir looked sheepish and shifted nervously, looking at his Neutrino friends.

"Oh," said Krupp, sounding let down, "not so fast, eh?"

"Oh, no no no. Don't get me wrong. The final velocity isn't bad." At this the Neutrino members clapped their hands over their mouths and stifled shrieks and laughs. "I was just going to let you see that for yourselves instead of throwing a lot of numbers at you."

"Well, that's fine!" said Krupp, sounding more sanguine. "Don't let us laymen interfere with your schedule. I'm sorry. Just go right ahead." He stepped back and crossed his arms as though planning to shut up for hours.

Casimir gave the empty bucket a tap and there were oohs and aahs as it floated smoothly and quietly down the rails, bounced off a stop at the end and floated back with no change in speed. He reinserted the one-kilogram brass cylinder. "Now let's try it. As you can see we have a momentum absorber set up at the other end of the lab."

The "momentum absorber" was ten squares of 3/8-inch plywood held parallel in a frame, spaced two inches apart to form a sandwich a couple of feet long. This was securely braced against the wall of the lab at the same level as the mass driver. had assumed that the intended target was a wastebasket floor beneath the "muzzle" of the machine, but now realized that Casimir was expecting the weight to fly about twenty feet without losing any altitude. "I suggest you all stand back in case something goes wrong," said Casimir, and feeling somewhat alarmed I stood way back and suggested that Sarah do likewise. Casimir made a last check of the circuitry, then hit a big red button.

The sound was a whizz followed by a rapid series of staccato explosions. It could be written as: ZZIKKH where the entire sound takes about a quarter of a second. None of us really saw anything. Casimir was already running toward the momentum absorber. When we got there, we saw that the first five layers of plywood had perfectly clean round holes punched through them, two more had messy holes, and the next layer had buckled, the brass cylinder wedged in place at its bottom. Casimir pulled out the payload with tongs and dropped it into an asbestos mitt he had donned. "It's pretty hot after all those collisions," he explained.

Everyone but Casimir was electrified. Even the Neutrino observers, who had seen it before, were awed, and laughed hysterically from time to time. Sarah looked as though whatever distrust she had ever had in technology had been dramatically confirmed. I stared at Casimir, realizing how smart he was. Virgil left, smiling. Krupp's little friend paced between mass driver and target, hands clasped behind back, a wide smile nestled in his silver-brown beard, while Krupp himself was astonished.

"Jesus H. Christ!" he yelled, fingering the holes. "That is the damnedest thing I've ever seen. Good lord, boy, how did you make this?"

Casimir seemed at a loss. "It's all done from Sharon's plans," he said blankly. "He did all the magnetic fieldwork. I just plugged in the arithmetic. The rest of it was machine-shop work. Nothing complicated about the machine."

"Does it have to be this powerful?" I said. "Don't get me wrong. I'm impressed as hell. Wouldn't it have been a little easier to make a slower one?"

"Well, sure, but not as useful," said Casimir. "The technical challenges only show up when you make it fast enough to be used for its practical purpose— which is to shoot payloads of ore and minerals from the lunar surface to an orbital processing station. For a low-velocity one we could've used air cushions instead of magnetic fields to float the bucket but there's no challenge in that."

"What's the muzzle velocity?" asked Krupp's guest, who had appeared next to me. He spoke quietly and quickly in an Australian accent. When I looked down at him, I realized he was Oswald Heimlich, Chairman of the Board of Trustees of American Megaversity and one of the richest men in the city — the founder of Heimlich Freedom Industries a huge defense contractor. Casimir obviously didn't know who he was.

"The final velocity of the bucket is one hundred meters per second, or about two hundred twenty miles per hour."

"And how could you boost that?"

"Boost it?" Casimir looked at him, startled. "Well, for more velocity you could build another just like this— "

"Yes, and put them together. I know. They're interconnectible. But how could you increase the acceleration of this device?"

"Well, that gets you into some big technical problems. You'd need expensive electronic gear with the ability to kick out huge pulses of power very quickly. Giant capacitors could do it, or a specialized power supply."

Heimlich followed all this, nodding incessantly. "Or a generator that gets its power from a controlled explosion."

Casimir smiled. "It's funny you should mention that. Some people are speculating about building small portable mass drivers with exactly that type of power supply— a chemical explosion— and using them to throw explosive shells and so on. That's what is called— "

"A railgun. Precisely."

Things began to fall into place for Casimir. "Oh. I see. So you want to know if I could build— basically a railgun."

"Sure. Sure," said Heimlich in an aggressive, glinting voice. "What's research without practical applications?" The question hung in the air.

Krupp took over, sounding much calmer. "You see, Casimir, in order to continue with this research— and you are off to an exceptionally fine start— you will need outside funding on a larger scale. Now, as good an idea as lunar mining is, no one is ever going to fund that kind of research. But railguns— whether you like it or not, they have very immediate significance that can really pull in the grants. I'm merely pointing out that in today's climate relating your work to defense is the best way to obtain funding. And I imagine that if you wanted to set up a specialized lab here to advance this kind of work, you might be able to get all the funding you'd want."

Casimir looked down at the shattered plywood in consternation. "I don't need an answer now. But give it some careful thought, son. There's no reason for you to be stuck in silly-ass classes if you can do this kind of work. Call me anytime you like." He shook Casimir's hand, Heimlich made a brief smiling spastic bow, and they walked out together.

Sarah quit the Presidency of the Student Government on the first of January. At the mass-driver demonstration, S. S. Krupp had simply ignored her, which was fine by Sarah as she had no desire to give the man a point-by-point explanation.

As for the death of Tiny, here the other shoe never dropped, though Sarah and Hyacinth kept waiting. His body was in especially poor condition when found, and the bullet holes might not have been detected even if someone had thought to look for them. The City police made a rare Plex visit and looked at the broken window and the electrocuted man on the floor, but apparently the Terrorists had cleaned up any blood or other evidence of conflict; in short, they made it all look like a completely deranged drunken fuck-up, an archetype familiar to the City cops.

The Terrorists wanted their own revenge. None of them had a coherent idea of what had happened. Even the two surviving witnesses had dim, traumatized memories of the event and could only say it had something to do with a woman dressed as a clown. As soon as I heard that the Terrorists were looking for someone called Clown Woman, I invited her over and we had a chat. I knew what her costume had been. Though she understood why I was curious, she suddenly adopted a sad, cold reserve I had never seen in her before.

"Some really terrible things happened that night. But I'm I Hyacinth is safe— okay? And we've been making plans to stay that way."

"Fine. I just— "

"I know. I'd love to tell you more. I'm dying to. But I won't, because you have some official responsibilities and you're the kind of person who carries them out, and knowing anything would be a burden for you. You'd try to help— but that's something you can't do. Can you understand that?"

I was a little scared by her lone strength. More, I was stunned that she was protecting me. Finally I shrugged and said, "Sounds as though you know what you're doing," because that was how it sounded.

"This has a lot to do with your resigning the Presidency?" I continued. Sarah was a little annoyed by my diplomacy, for the same reason S. S. Krupp would have been.

"Bud, I don't need some terrific reason for resigning. If I'm spending time on a useless job I don't like, and I find there are better things to do with that time, then I ought to resign." I nodded contritely, and for the first time she was relaxed enough to laugh. On her way out she gave me a long platonic hug, and I still remember it when I feel in need of warmth.

They got the wading pool and the garden hose on a two-hour bus ride to a suburban K-Mart. Hyacinth inflated it in the middle of Sarah's room while Sarah ran the hose down the hall to the bathroom to pipe in hot water. Once the pool was acceptably full and foamy, they retrieved the hose, locked the door and sealed off all windows with newspaper and all cracks around the door with towels and tape. They lit a few candles but blew most of them out when their eyes adjusted. The magnum of champagne was buried in ice, the water was hot, the night was young. Hyacinth's .44 was very intrusive, and so Sarah filed it under G for Gun and they had a good laugh.

Around 4:00 in the morning, to Sarah's satisfaction, Hyacinth passed out. Sarah allowed herself to do likewise for a while. Then she dragged Hyacinth out onto the rug, dried her and hoisted her into bed. They slept until 4:32 in the afternoon. Sleet was ticking against the window. Hyacinth cut a slit in the window screen and they fed the hose outside and siphoned all the bathwater out of the pool and down the side of the Plex. They ate all of Sarah's mother's banana bread, thirty-two Chips Ahoys, three bowls of Captain Crunch, a pint of strawberry ice cream and drank a great deal of water. They then gave each other backrubs and went to sleep again.

"Keeping my .38 clean is a pain in the ass," said Sarah at one point. "It picks up a lot of crud in my backpack pocket." "That's one reason to carry a single-action," said Hyacinth. "Less to go wrong if it's dirty."

A long time later, Sarah added, "This is pretty macho. Talking about our guns."

"I suppose it's true that they're macho. But they are also guns. In fact, they're primarily guns."

"True."

They also discussed killing people, which had become an important subject with them recently.

"Sometimes there isn't any choice," Sarah said to Hyacinth, as Hyacinth cried calmly into her shoulder. "You know, Constantine punished rapists by pouring molten lead down their throats. That was a premeditated, organized punishment. What you did was on the spur of the moment."

"Yeah. Putting on protective clothes, loading my gun, tracking them down and blowing one away was really on the spur of the moment."

"All I can say is that if anyone ever deserved it, he did." Three Terrorists ambled down the hall past Sarah's door, chanting "Death to Clown Woman!"

"Okay, fine," said Hyacinth, and stopped crying. "Granted. I can't worry about it forever. But sooner or later they're going to figure out who Clown Woman is. Then there'll be even more violence."

"Better them to be violent against us," said Sarah, "than against people who don't even understand what violence is."

Sarah was busy taking care of herself that semester. This made more sense than what the rest of us were doing, but it did not make for an eventful life. At the same time, a very different American Megaversity student was fighting the same battle Sarah had just won. This student lost. The tale of his losing is melancholy but much more interesting.

Every detail was important in assessing the situation, in determining just how close to the brink Plexor was! The obvious things, the frequent transitions from the Technological universe to the Magical universe, those were child's play to detect; but the evidence of impending Breakdown was to be found only in the minutiae. The extra cold-water pipe; that was significant. What had suddenly caused such a leak to be sprung in the plumbing of Plexor, which had functioned flawlessly for a thousand years? And what powerful benign hand had made the switch from one pipe to the other? What prophecy was to be found in the coming of the Thing of the Earth in the test run of Shekondar? Was some great happening at hand? One could not be sure; the answer must be nested among subtleties. So this one spent many days wandering like a lone thaumaturge through the corridors of the Plex, watching and observing, ignoring the classes and lectures that had become so trivial.

With the help of an obsequious MARS lieutenant he was allowed to inspect the laboratory of the secret railgun experiments. Here he found advanced specialized power supplies from Heimlich Freedom Industries. The lieutenant, a Neutrino member of four years' standing, hooked the output of one power supply to an oscilloscope and showed him the very high and sharp spike of current it could punch out— precisely the impulses a superfast mass driver would need to keep its payload accelerating explosively right up to the end. This one also observed a test of a new electromagnet. It was much larger than those used for the first mass driver, wound with miles of hair-thin copper wire and cooled by antifreeze-filled tubes. A short piece of rail had been made to test the magnet. It was equipped with a bucket designed to carry a payload ten centimeters across! This one watched as a violent invisible kick from the magnet wrenched the bucket to high velocity and slammed it to the cushion at the rail's end; the heavy payload shot out, boomed into a tarp suspended about five feet away, and fell into a box of foam-rubber scraps. It was the same pattern he saw everywhere. A peaceful lunar mining device had, under the influence of Shekondar the Fearsome, metamorphosed into a potent weapon of great value to the forces of Good.

He gave the lieutenant a battlefield promotion to Captain. He wanted to stay and continue to watch, but it had been a long day; he was tired, and for a moment his mind seemed to stop entirely as he stood by the exit.

Then came again the creeping sense of Leakage, impossible to ignore; his head snapped up and to the right, and, speaking across the dimensional barrier, Klystron the Impaler told him to go to dinner.

Klystron the Impaler was only Klystron the Impaler when he was in a Magical universe. The rest of the time he was Chris the Systems Programmer— a brilliant, dashing, young, handsome terminal jockey considered to be the best systems man on the giant self-contained universe-hopping colony, Plexor. From time to time Plexor would pass through the Central Bifurcation, a giant space warp, and enter a Magical universe, fundamentally altering all aspects of reality. Though the structure of Plexor itself underwent little change at these times, everything therein was converted to its magical, pretechnological analog. Guns became swords, freshmen became howling savages, Time magazine became a hand-lettered vellum tome and Chris the Systems Programmer— well, brilliant people like him became sorcerers, swordspeople and heroes. The smarter they were— the greater their stature in the Technological universe— the more dazzling was their swordplay and the more penetrating their spells. Needless to say, Klystron the Impaler was a very great hero-swordsman-magician indeed.

Of course, Plexorians tended to be that way to begin with. Only the most advanced had been admitted when Plexor was begun, and it was natural that their distant offspring today should tend toward the exceptional. Of those lucky enough to be selected for Plexor, only the most adaptable had any stomach for the life once they got there and, every month or so, found their waterbeds metamorphosing into heaps of bearskins. Klystron/Chris liked to think of the place as a pressure cooker for the advancement of humanity.

But even the most perfect machine could not be insulated from the frailty and stupidity of the human mind. In the early days of Plexor every inhabitant had understood the Central Bifurcation, had respected the distinction between technology and magic, and had shown enough discipline to ensure that division. Within the past several generations, though, ignorance had come to this perfect place and Breakdown had begun. Recent generations of Plexorians lacked the enthusiasm and commitment of their forebears and displayed ignorance which was often shocking; recently it had become common to suppose that Plexor was not a free-drifting edosociosystem at all, that it was in fact a planetoidal structure bound to a particular universe. Occasionally, it was true, Plexor would materialize on the ground, in a giant city or a barbarian kingdom. Its makers, a Guild of sorcerers and magicians operating in separate universes through the mediation of Keldor, had created it to be self-sufficient and life-supporting in any habitat, with a nuclear fuel source that would last forever. But to believe that one particular world was always out there was a blindness to reality so severe that it amounted to rank primitivism amidst this sophisticated colony of technocrats. It was, in a word, Breakdown— a blurring of the boundary— and such was the delicacy of that boundary between the universes that mere ignorance of its existence, mere Breakdown-oriented thinking and Breakdown-conducive behavior, was sufficient to open small Leaks between Magic and Technology, to generate an unholy Mixture of the two opposites. It was the duty of the remaining guardians of the Elder Knowledge. such as Klystron/Chris, to expurgate such mixtures and restore the erstwhile purity of the two existences of Plexor.

In just the past few weeks the Leaks had become rents, the Mixture ubiquitous. Now Barbarians sat at computer terminals in the Computing Center unabashed, pathetically trying, in broad daylight, to run programs that were so riddled with bugs the damn things wouldn't even compile, their recent kills stretched out bleeding between their feet awaiting the spit. Giant rats from another plane of existence roamed free through the sewers of the mighty technological civilization, and everywhere Chris the Systems Analyst found dirt and marrow-sucked bones on the floor, broken light fixtures, graffiti, noise, ignorance. He watched these happenings, not yet willing to believe in what they portended, and soon developed a sixth sense for detecting Leakage. That was in and of itself a case of Mixture; in a Technological universe, sixth senses were scientifically impossible. His new intuition was a sign of the Leakage of the powers of Klystron the Impaler into a universe where they did not belong. In recognition of this, and to protect himself from the ignorant, Klystron/Chris had thought it wise to adopt the informal code name of Fred Fine.

He had denied what was coming for too long. Despite his supreme intelligence he was hesitant to accept the hugeness of his own personal importance.

Until the day of the food fight: on that day he came to understand the somber future of Plexor and of himself. It happened during dinner. To most of those in the Cafeteria it was just a food fight, but to "Fred Fine" it was much more significant, a preliminary skirmish to the upcoming war, a byte of strategic data to be thoughtfully digested.

He had been contemplating an abstract type of program structure, absently shuffling the nameless protein-starch substance from tray to mouth, when a sense of strangeness had verged on his awareness and dispersed his thoughts. As he looked up and became alert, he also became aware that (a) the food was terrible; (b) the Caf was crowded and noisy; and (c) Leakage was all around. His mind now as alert as that of Klystron before a melee, he scanned the Cafeteria from his secure corner (one of only four corners in the Cafeteria and therefore highly prized), stuffing his computer printout securely into his big locking briefcase. Though his gaze traversed hundreds of faces in a few seconds, something allowed him to fix his attention on a certain few: eight or ten, with long hair and eccentric clothing, who were clearly looking at one another and not at the gallons of food heaped on their Fiberglass trays. The sixth sense of Klystron enabled Chris to glean from the whirl of people a deeply hidden pattern he knew to be significant.

He stood up in the corner, memorizing the locations of those he had found, and switched to long-range scan, assisting himself by following their own tense stares. His eyes flicked down to the readout of his digital calcu-chronograph and he noted that it was just seconds before 6:00. Impatiently he polled his subjects and noted that they were now all looking toward one place: a milk dispenser near the center of the Cafeteria, where an exceptionally tall burnout stood with a small black box in his hand!

There was a sharp blue flash that made the ceiling glow briefly— the black box was an electronic flash unit— and all hell broke loose. Missiles of all shapes and colors whizzed through his field of vision and splathunked starchily against tables, pillars and bodies. Amid sudden screaming an entire long table was flipped over, causing a hundredweight of manicotti and French fries to slide into the laps of the unfortunates on the wrong side. Seeing the perpetrators break and dissolve into the milling dinnertime crowd, the victims could only respond by slinging handfuls of steaming ricotta at their disappearing backsides. At this first outbreak of noise and action the Cafeteria quieted for a moment, as all turned toward the disturbance. Then, seeing food flying past their own heads, most of the spectators united in bedlam. The Terrorist sections seemed to have been expecting this and joined in with beer-commercial rowdiness. Several tables of well-dressed young women ran frantically for the exits, in most cases too slowly to prevent the ruination of hundreds of dollars' worth of clothes a head. Many collapsed squalling into the arms of their patron Terrorist organizations. The Droogs opened a milk machine, pulled out a heavy poly-bag of Skim and slung it into the midst of what had been an informal gathering of Classics majors, with explosive results.

All was observed intently by Klystron/Chris, who stood calm and motionless in his corner holding his briefcase as a shield. Though the progress of the fight was interesting to watch, it was hardly as important as the behavior of the instigators and the reactions of the Cafeteria staff.

Of the instigating organization, some were obliged to flee immediately in order to protect themselves. These were the agents provocateurs, the table-tippers and tray-slingers, whose part was already played. The remainder were observers, and they stood in carefully planned stations around the walls of the Cafeteria and watched, much as Chris did. Some snapped pictures with cheap cameras.

This picture-taking began in earnest when, after about fifteen seconds, the reactive strike began. The cooks and servers had instantly leapt to block the doors of the serving bays, which in these circumstances had the same value as ammunition dumps. Pairs of the larger male cooks now charged out and drew shut the folding dividers which partitioned the Cafeteria into twenty-four sections. Meanwhile, forty-eight more senior Cafeteria personnel and guards fanned out in organized fashion, clothed in ponchos and facemasks. In each section, one of them leapt up on a table with a megaphone to scream righteousness at the students, while his partner confronted particularly active types. Klystron/Chris's view of the fight was abruptly reduced to what he could see in his own small section.

Among other things he saw eight of the Roy G Biv Terrorist Group overturn the table on which the local official stood, sending him splaying on hands and knees across the slick of grease and tomato sauce on the floor. His partner skidded after him and swiveled to protect their backs from the Terrorists, who had huddled and were mumbling menacingly. For the first time Klystron/Chris felt the hysterical half-sick excitement of approaching violence, and he began to edge along the wall toward a more strategically sound position.

One of the Terrorists went to the corner where the sliding partitions intersected, blocking the only route of escape. The men in the room moved away uneasily; the women pressed themselves against the wall and sat on the floor and tried to get invisible. Then the Roy G Biv men broke; two went for the still-standing official, one for the man who was just staggering to his feet with the dented megaphone. Abruptly, Klystron/Chris stepped forward, took from his briefcase a small weapon and pulled the trigger. The weapon was a flash gun, a device for making an explosively intense flash of light that blinded attackers. Everyone in front of the weapon froze. As they were putting their hands to their eyes, he pulled out his Civil War bayonet, jammed it into a fold in the sliding partition and pulled it down to open a six-foot rent. He led the tactical retreat to the adjoining section, which was comparatively under control.

The officials here were not amused. A stocky middle-aged man in a brown suit stomped toward Klystron/Chris with death in his eye. He was stopped by a chorus of protest from the refugees, who made it clear that the real troublemakers were back there. And that was how Klystron/Chris avoided having any of these seriously Mixed officials discover his informal code name.

But what was the strategic significance? He knew it had been done by Barbarians. Despite the carefully tailored modern clothes they used to hide their stooping forms and overly long arms, he recognized their true nature from the ropy scars running along their heavy overhanging brows and the garlands of rodent skulls they wore around their necks. Had it not been for the cameramen, he would have concluded that this was nothing more than a purposeless display of the savages' contempt for order. But the photographers made it clear that this riot had been a reconnaissance-in-force, directed by an advanced strategic mind with an crest in the Cafeteria's defenses. And that, in turn, implied an upcoming offensive centered on the Cafeteria itself. Of course! In here was enough grub to feed a good-sized commando force for years, if rationed properly; it would therefore be a prime objective for insurrectionists planning to seize and hold large portions of Plexor. But why? Who was behind it? And how did it connect with the other harbingers of catastrophe?

Once upon a time, a mathematically inclined friend of Sarah's, one Casimir Radon, had estimated that her chances of running into a fellow Airhead at dinner were no better than about one in twenty. As usual he was not trying to be annoying or nerdish, but nevertheless Sarah wished for a more satisfying explanation of why she could get no relief from her damned neighbors. One in twenty was optimistic. At times she thought that they were planting spies in her path to take down statistics on how many behavioral standards she broke, or to drive her crazy by asking why she had really resigned the Presidency.

She was annoyed but not surprised to find herself eating dinner with Mari Meegan, Mari's second cousin and Toni one night. Relaxed from a racquetball game, she made no effort to scan her route through the Caf for telltale ski masks. So as she danced and sideslipped her way toward what looked like an open table, she was blindsided by a charming squeal from right next to her. "Sarah!" Too slow even to think of pretending not to hear, she looked down to see the three color-coordinated ski masks looking back at her expectantly. She despised them and never wanted to see them again, ever, but she also knew there was value in following social norms, once in a while, to forestall hatred and God knows what kinds of retribution. The last thing she wanted was to be connected with Clown Woman. So she smiled and sat down. It was not going to be a great meal, but Sarah's conversation support system was working well enough to get her at least through the salad.