Dinosaur Beach had been so named because a troop of small allosaur-like reptiles had been scurrying along it when the first siting party had fixed in there. That had been sixty years ago, Nexx Subjective, only a few months after the decision to implement Project Timesweep.

The idea wasn"t without logic. The First Era of time travel had closely resembled the dawn of the s.p.a.ce age in some ways-notably, in the trail of rubbish it left behind. In the case of the s.p.a.ce garbage, it had taken half a dozen major collisions to convince the early s.p.a.ce authorities of the need to sweep circ.u.mterrestrial s.p.a.ce clean of fifty years debris in the form of spent rocket casings, defunct telemetry gear, and derelict relay satellites long lost track of. In the process they"d turned up a surprising number of odds and ends, including lumps of meteoric rock and iron, chondrites of clearly earthly origin, possibly volcanic, the mummified body of an astronaut lost on an early s.p.a.ce walk, and a number of artifacts that the authorities of the day had scratched their heads over and finally written off as the equivalent of empty beer cans tossed out by visitors from out-system.

That was long before the days of Timecasting, of course.

The Timesweep program was a close parallel to the s.p.a.ce sweep. The Old Era temporal experimenters had littered the timeways with everything from early one-way timecans to observation stations, dead bodies, abandoned instruments, weapons and equipment of all sorts, including an automatic mining setup established under the Antarctic icecap which caused headaches at the time of the Big Melt.

Then the three hundred years of the Last Peace put an end to that; and when temporal transfer was rediscovered in early New Era times, the lesson had been heeded. Rigid rules were enforced from the beginning of the Second Program, forbidding all the mistakes that had been made by the First Program pioneers.

Which meant that the Second Program had to invent its own disasters-which it had, in full measure. Thus the Kargs.

Karg: a corruption of "cargo," referring to the legal decision as to the status of the machine-men in the great Transport Accommodation Riots of the mid-Twenty-eighth Century.

Kargs, lifeless machines, sent back from the Third Era in the second great Timesweep attempt, designed to correct not only the carnage irresponsibly strewn across the centuries by the Old Era temporal explorers, but to eliminate the even more disastrous effects of the Second Program Enforcers.

The Third Era had recognized the impossibility of correcting the effects of human interference with more human interference. Machines which registered neutral on the life-balance scales could do what men could not do: could manipulate affairs without disturbing the delicate and poorly understood equations of vital equilibrium, to restore the integrity of the Temporal Core.

Or so they thought. After the Great Collapse and the long night that followed, Nexx Central had arisen to control the Fourth Era. The Nexx Timecasters saw clearly that the tamperings of prior eras were all part of a grand pattern of confusion; that any effort to manipulate reality via temporal policing was doomed only to further weaken the temporal fabric.

When you patch time, you poke holes in it; and patching the patches makes more holes, requiring still larger patches. It"s a geometric progression that soon gets out of hand; each successive salvage job sends out waves of entropic dislocation that mingle with, reinforce, and complicate the earlier waves-and no amount of paddling the surface of a roiled pond is going to restore it to a mirror surface.

The only solution, Nexx Central realized, was to remove the first causes of the original dislocations. In the beginning, of course, the disturbances set up by Old Era travelers were mere random violations of the fabric of time, created as casually and as carelessly as footprints in the jungle. Later, when it had dawned on them that every movement of a grain of sand had repercussions that went spreading down the ages, they had become careful. Rules had been made, and even enforced from time to time. When the first absolute prohibition of time meddling came along, it was already far too late. Subsequent eras faced the fact that picnics in the Paleozoic might be fun, but exacted a heavy price in the form of temporal discontinuities, aborted entropy lines, and probability anomalies. Of course, Nexx, arising as it did from this adulterated past, owed its existence to it; careful tailoring was required to undo just enough damage to restore vitality to selected lines while not eliminating the eliminator. Superior minds had to be selected and trained to handle the task.

Thus, my job as a Nexx field agent: to cancel out the efforts of all of them-good and bad, constructive or destructive; to allow the wounds in time to heal, for the great stem of life to grow strong again.

It was a worthy profession, worth all it cost. Or so the rule book said.

I started off along the sh.o.r.e, keeping to the damp sand where the going was easier, skirting the small tidal pools and the curving arcs of sea sc.u.m left by the retreating tide.

The sea in this era-some sixty-five million years B.C.-was South-Sea-island blue, stretching wide and placid to the horizon. There were no sails, no smudges of smoke, no beer cans washing in the tide. But the long swells coming in off the Eastern Ocean-which would one day become the Atlantic-crashed on the white sand with the same familiar carrump-whoosh! that I had known in a dozen eras. It was a comforting sound. It said that after all, the doings of the little creatures that scuttled on her sh.o.r.es were nothing much in the life of Mother Ocean, age five billion and not yet in her prime.

The station was a quarter of a mile along the beach, just beyond the low headland that jutted out into the surf; a small, low, gray-white structure perched on the sand above the high-tide line, surrounded by tree ferns and club mosses, both for decoration and to render the installation as inconspicuous as possible, on the theory that if the wildlife were either attracted or repelled by a strange element in their habitat, uncharted U-lines might be introduced into the probability matrix that would render a thousand years of painstaking-and painful-temporal mapping invalid.

In a few minutes I"d be making my report to Nel Jard, the Chief Timecaster. He"d listen, ask a few questions, punch his notes into the Masterplot and pour me a drink. Then a quick and efficient session under the memory-editor to erase any potentially disquieting recollections arising from my tour of duty in the Twentieth Century-such as Lisa. After that, a few days of lounging around the station with other between-jobs personnel, until a new a.s.signment came up-having no visible connection with the last one. I"d never learn just why the Karg had been placed where it was, what sort of deal it had made with the Third Era Enforcer-the man in black-what part the whole thing played in the larger pattern of the Nexx grand strategy.

And probably that was just as well. The panorama of time was too broad, the warp and the woof of its weaving too complex for any one brain to comprehend. Better to leave the mind free to focus on the details of the situation at hand, rather than diffuse it along the thousand dead-end trails that were the life of a Timecast Agent. But Lisa, Lisa . . .

I put the thought of her out of my mind-or tried to-and concentrated on immediate physical sensations: the hot, heavy air, the buzzing insects, the sand that slipped under my feet, the sweat trickling down my temples and between my shoulder blades. Not that those things were any fun in themselves. But in a few minutes there"d be cool clean air and soft music, a stimbath, a hot meal, a nap on a real air couch. . . .

A couple of off-duty agents, bright-eyed, efficient, came out to meet me as I came across the slope of sand to the edge of the lawn, through the open gate and in under the shade of the protopalms. They were strangers to me, but they greeted me in the casually friendly way that you develop in a lifetime of casual friendships. They asked me the routine questions about whether I had had a rough one, and I gave them the routine answers.

Inside the station the air was just as cool and clean as I"d remembered-and as sterile. The stimbath was nice-but I kept thinking of the iron-stained bathtub back home. The meal afterward was a gourmet"s delight: reptile steak smothered in giant mushrooms and garnished with prawns, a salad of club-moss hearts, a hot-and-cold dessert made by a barrier-layer technique that wouldn"t be perfected for another sixty-five million years but didn"t compare with Lisa"s lemon ice-box pie with graham-cracker crust. And the air couch was nice, but not half as nice as the hard old bed with the bra.s.s frame in the breathlessly hot room with the oak floor and the starched curtains, and Lisa curled close to me. . . .

Jard let me sleep it out before the debriefing. He was a small, hara.s.sed-looking man in his mid-fifties, with an expression that said he had seen it all and hadn"t been much impressed. He gave me his tired smile and listened to what I had to say, looking out the window at the same view he"d been looking at every day for five years. He liked it that I"d gotten the tape; Kargs usually managed to destruct when cornered; my slug in the emergency computing center had prevented it this time: thus the elaborate play to get him in position with his suspicions lulled. It had all been very cleverly planned and executed, and now I was tired of it, tired of the role I"d been playing, tired of the whole d.a.m.ned thing.

But that was just a temporary post-mission letdown. As soon as I"d had my brain scrubbed, and had rested a few days and cleared my mind of those annoying wisps of nostalgic thought, I"d be raring to go again.

Or so I hoped. Why not? I always had in the past.

Jard asked me to hold the memory-wipe until he"d had an opportunity to go through the tape in depth. I started to protest, but some vague idea of not sounding like a whiner stopped me.

I spent the rest of the day mooching around the station, thinking about Lisa.

It was a simple case of compulsive transference, or neurotic sublimation, I knew that. At least I knew the words. But every train of thought led back to her. If I tasted a daka-fruit-extinct since the Jura.s.sic-I thought Lisa would like this, and I"d imagine her expression if I brought a couple home in a brown paper sack from the IGA store at the corner, pictured her peeling them and making a fruit salad with grated coconut and blanched almonds. . . .

There was a beach party that evening, down on the wide, white sand where it curved out in a long spit to embrace a shallow lagoon, where every now and then something made a splash that was too big to be a fish. Cycads grew on the point of land and on the sand bar that was busy growing into a key. They looked like beer barrels with flowers on their sides and palm fronds sticking out of their tops. There were a few unfinished-looking pines and the usual scattering of big ferns and clumps of moss that were trying to be trees. There weren"t many bothersome insects; just big, blundery ones, and the small darting batlike reptiles were keeping them under control.

I sat on the sand and watched my compatriots: strong, healthy, handsome men and women, swimming in the surf inside the sonic screen set up to discourage the ichthyosaurs, chasing each other up and down the sand-and catching each other-while the guards posted in the pits at each end of the beach watched for wandering maneaters. We built a big fire-of driftwood fetched in from a locus a few million years downstream. We sang songs from a dozen eras, ate our roast baby stegosaurian, and drank white wine imported from eighteenth-century France, and felt like the lords of creation. And I thought about Lisa.

I had trouble sleeping that night. My appointment with the cepher was scheduled for 8:00 A.M. I was up before six. I ate a light breakfast and went for a walk on the beach to enjoy a few last thoughts of Lisa and wonder if somehow in our wisdom we had missed the point somewhere. It wasn"t the kind of question that had an answer, but it kept my mind occupied while I put a mile or two between me and the station. I sat for half an hour and looked at the sea and wondered what I"d do if something large and hungry stalked out of the herbage behind me. I didn"t know; I didn"t even much care.

A bad train of thought, Ravel, I told myself. Time to get back and tidy up your mind, before you get carried away and start thinking about how easy it would be to step into the transfer booth and drop yourself back into 1936 a block from the house, ten minutes after you left. . . .

I had gotten that far in my ruminations when I heard the shots.

It"s a curious thing how in moments of stress, the mind jumps to the inconsequential. I was running, without having consciously started, sending up a spatter of spray as I dashed through the tongue of a wave that slid across in my path; and I was thinking: I won"t be stepping into that cooled air and antiseptic music again; no hot meal, no stimbath, no nap on a real air couch. . . . And no Lisa, never again Lisa . . .

I cut up across the soft sand-drift of the point, slipping and sliding as I ploughed my way upslope, crashed through a screen of palmetto at the crest, and was looking down at the station.

I don"t know what I expected to see; the detonations I had heard were as much like Old Era hardshots as anything in my experience. What I saw was a pair of bulky, gray-brown machines, track-driven, obviously armored, in the fifty-ton size range, parked on the sand a few hundred yards from the station. No smoking gun muzzles were visible, but the chunk missing from the corner of the building was adequate testimony that guns were present, even without the rackety-boom! and the spurt of fire that came from the featureless curve of the prow of the nearer machine. The other was in trouble. One track was mangled, and smoke was leaking from a variety of places on its surface. It gave a little hop and almost invisible fire jetted from the same spots. I dropped flat in time to get the shock wave against my ribs: a kick from a buried giant.

I came up at a dead run, spitting sand and not thinking too clearly, but absolutely, unconditionally convinced that whatever was going on down there, the only Timecast booth this side of the Pleistocene was inside the station, and the nearer I got to it before they got me, the happier I"d die.

But no one was paying any attention to me and my aspirations. The still-functional warcar-Third Era, the data processor between my ears told me inconsequentially-was coming on, firing as it came. Jard must have succeeded in erecting at least a partial screen; rainbow light flared and darted coronalike over the station with each shot. But the defenses had been designed to ward off blundering brontosaurians, not tactical implosives. It wouldn"t be long. . . .

I aborted that thought and put my head down and sprinted. Fire ran across the ground in front of me and winked out; the blast sent me skittering like a paper cutout in a brisk wind. I rolled, with some half-baked idea of evading any random shots somebody might be tossing my way, and came to my feet ten of the widest yards anybody ever crossed from that welcoming hole gaping in the east wall where the espalier had been. Through it I could see what was left of a filing cabinet and the internal organs of a resage chair and some twisted and blackened rags of metal that had been restful tan wall panels; but none of it seemed to get any closer. I was running with all I had, through foot-deep glue, while h.e.l.l came to a head and burst around me.

And then I was going through in a long graceful dive that fetched up against an oversized anvil someone had carelessly left lying around the place. . . .

I came drifting back out of a thick fog full of little bright lights and bellowing monsters and looked up into the sweat-slick face of Nel Jard, Station Chief.

"Pull yourself together, man!" he was yelling. He had to yell to be heard over the continuous booming of the bombardment. "Everybody else is clear. I waited for you-knew you were back inside the field. Had to tell you. . . ." What he had to tell me was drowned out in a crash that made the earlier sound effects sound like a warm-up. Things fell around us. There was a throat-burning reek of ozone in the air, along with the scents of smoke and blood and pulverized stone and hot iron. I got my feet under me in time to see Jard disappearing through the door into the Ops room. I tottered after him, saw him punching a pattern into the board. The red emergency lights went on and the buzzer started its squawk and cut off abruptly. Jard turned and saw me.

"No!" he shouted, waving me off. "Get out, Ravel! Didn"t you hear a word I told you? You"ve got to . . . out . . . co-ordinates-"

"I can"t hear you," I shouted back, and couldn"t hear my own words. Jard grabbed my arm, hustled me toward the floor-drop that led to the utility tunnel.

"I"ve got to shift the station to null-phase, you understand? Can"t let them capture it. . . ." The door was up and I was being dumped over the edge. It was all happening too fast; bewildering. A h.e.l.l of a way to treat a sick man . . . The impact of the floor hitting my head jarred it clear for the moment.

"Run for it," Jard was calling after me, from a million miles away. "Get as far as you can. Luck, Ravel . . ."

His voice was gone and I was on all fours, then stumbling to my feet, then running, more or less. It was what Nel wanted, and he was the boss.

Then the world blew up and sent me spinning head-over-heels into limbo, and a thousand tons of hot sand poured down on top of me and sealed me away for all eternity.

5.

Well, maybe not eternity, a small voice seemed to be saying in a matter-of-fact tone.

"Close enough," I said, and got a mouthful of sand. I tried to draw a breath to spit it out and got a noseful of the same. That must have triggered some primitive instincts, because suddenly I was swimming hard with both hands and both feet, clawing upward through sand, breaking through into heat and the stink of charred plastics-and air. Dusty, smoky air, but air. I coughed and snorted and breathed some of it and looked around me.

I was lying in the utility tunnel, the walls of which were buckled and bulged as if they"d been half melted. The floor was drifted a foot deep in sand, out of which I had just dug my way. I tried to make my brain work. . . .

The tunnel led to the pump room, I knew, from which a ladder led to the surface, an arrangement designed for minimal disturbance of the local scenery. All I had to do was continue in the present direction, climb the ladder, and. . . .

I"d worry about the and later, I decided. I was still congratulating myself on my coolness under fire when I happened to notice that for a tunnel twelve feet under the surface, the light was awfully good. It seemed to be coming from behind me. I looked back, saw a tangle of steel, through the interstices of which brilliant sunlight was pouring in dusty bars.

After a dozen or so yards the going was easier; not so much sand and debris here. The pump-room door gave me a little trouble until I remembered to pull, not push. The equipment there was all intact, ready to pump any desired amount of clean, fresh spring water up from 120 feet down. I patted the nearest pump and got a grip on the ladder. I was still dizzy and weak, but no dizzier or weaker than a landlubber in his first sea-squall. At the top, the motor whined when I pushed the b.u.t.ton; the lid cycled open, dumping sand and a small green lizard. I crawled out and took a short breather and turned to see what there was to see.

There was the long curve of beach, pitted now, and criss-crossed by tank-tracks, and the tongue of jungle that stretched almost to the sh.o.r.e along the ridge. But where the station had been, there was nothing but a smoking crater.

I lay flat on the nice warm sand and looked at the scene with gritty eyes that wept copiously in the glare of the tropical Jura.s.sic sun and felt sweat trickle down my forehead, and down my chest inside my shirt, while images went swirling through my brain: the station, the first time I had seen it, on my first jump, all those years ago. The neat, impersonal little wardrooms that almost came to seem like home after a while, always waiting for you at the end of a tough a.s.signment; the other agents, male and female, who came and went; the in-conversation around the tables in the dining room, the crisp cleanliness, the efficiency; even the big board in Ops that showed the minute-by-minute status of the Timesweep effort up and down the ages. But the big board wasn"t there any more, or the miles of microtape records, or the potted gingko tree in the lounge: all melted down to slag.

I was remembering Nel Jard, yelling to me to get out . . . and something else. He"d given me a message. Something important, something I was supposed to tell somebody, someday. An exercise in futility. I"d had my last talk with a human being. I was stranded, stranded as no other man had ever been, with the possible exception of a few other Nexx agents who had dropped off the screens in far places.

But none as far as this.

On that thought, I let my head drop and the dark curtain fall.

6.

When I woke the sun was setting and I was aching in places I"d forgotten I owned. Itching, too. Oversized mosquitoes that didn"t seem at all surprised to find a mammal where no mammals ought to be had settled down with a commendably philosophic att.i.tude to take a meal where they found it. I batted the most persistent ones away and walked down to see what was to be seen. I didn"t appear to have any major injuries, just plenty of small cuts and large bruises and the odd contusion here and there. I reached the edge of the pit where the station had been and looked at the ruins: a fused gla.s.s bowl a hundred yards in diameter surrounded by charred plant life. Nothing had survived-no people, no equipment. And worst of all, of course, there"d be no outjump to Nexx Central with a report of what had happened-or to any other time or place.

Someone, possibly Third Era-or someone masquerading as Third Era-had blasted the station with a thoroughness I wouldn"t have believed possible. And how had it been possible for them to find the place, considering the elaborate security measures surrounding the placement of the 112 official staging stations scattered across Old Era time? As for Nexx Central, n.o.body knew where it was, not even the men who had built it. It floated in an achronic bubble adrift on the entropic stream, never physically existing in any one s.p.a.ce-time locus for a finite period. Its access code was buried under twelve layers of interlocked ciphers in the main tank of the Nexxial Brain. The only way to reach it was via a jump station-and not just any jump station: it had to be the one my personal jumper field was tuned to.

Which was a half-inch layer of green gla.s.s lining a hollow in the sand.

An idea appeared like a ghastly grin.

The personal emergency jump gear installed in my body was intact. There was enough E-energy in the power coil for a jump-somewhere. I lacked a target, but that didn"t mean I couldn"t go. All it meant was that I wouldn"t know where I"d land-if anywhere.

A lot of horror stories had circulated back at Nexx Central about what happened to people who misfired on a jump. They ranged from piecemeal reception at a dozen stations strung out across a few centuries to disembodied voices screaming to be let out. Also, there were several rules against it.

The alternative was to set up housekeeping here on the beach, with or without dinosaurs, and hope that a rescue mission arrived before I died of heat, thirst, reptiles, boredom, or old age.

It called for some thinking over.

There were a few chunks of masonry scattered among the charred stumps of club mosses; I could build a fireplace out of them, kill a lizard and broil him for dinner. . . .

The idea lacked charm, but I was reluctant to discard it out of hand. It was either that or risk my ident.i.ty on an experiment that I had already been a.s.sured by experts was bound to end in disaster. After all, there was no particular hurry. I was bruised, but alive; I wouldn"t starve for a few days; there was water available from the pump house. And maybe the destruction of the station had registered on somebody"s telltale board somewhere; maybe at this moment a relief team in crisp field-tan was a.s.sembling to jump out to the rescue.

It was almost dark now. The stars were glittering through the gloaming, just as if disaster hadn"t entered the biography of Igor Ravel, Timesweeper. The surf pounded and whooshed, indifferent to the personal problems of one erect biped who had no business being within sixty-five million years of here.

As for me, I had to go to the toilet.

It seemed a rather inconsequential thing to be doing, urinating on the magic sands of the past, while looking up at the eternal stars.

After that, I mooched around a little longer, looking for a lingering trace of the magic that had been there once. Then I dug a pit in the sand and went to sleep.

7.

Dawn came, and with it the dinosaurs. I had seen them before, at a distance, usually; small, shy creatures that skittered out of sight at the first touch of the subsonic beams Jard had rigged up to discourage them. Before my time, it seemed, there had been a few incidents of big specimens wandering a little too close to the vegetable garden and having to be driven off with improvised noisemakers. They were too stupid to be dangerous, it was understood, except for the danger of getting stepped on, or accidentally grazed along with a clump of foliage.

This time there were three of them. Big ones, and no subsonics available, not even an ordinary noisemaker, except for my vocal cords.

Once, I remembered, a "caster named Dowl, out for a swim, had been trapped on the beach by a saurian with impressive teeth which had popped out of the woods between him and the station. He "d gotten out of it with nothing worse than a case of delirium tremens; the behemoth had walked past him without a glance. He was too small a tidbit, the theory was, to interest a stomach as big as that one.

I didn"t find that thought consoling.

The trio coming my way were of a previously unrecorded variety we had named the Royal Jester, because of their silly grin and the array of bright-colored decorations sprouting like baubles from the cranium. They also had legs like an oversized ostrich, a long neck, and far too many teeth.

I stayed where I was, flat on the sand, and played boulder while they stalked toward me, shimmering in the heat haze. There were two big ones and one giant, eighteen feet at the shoulder if he was an inch. As they got closer, I could smell the rank, cuc.u.mber-and-dung smell of them, see the strips and patches of reticulated purple and yellow hide scaling from their backs, hear the hiss and wheeze of their breathing. They were big machines, calling for a lot of air turnover. I busied myself with some abortive calculations involving lung capacity, O2 requirements per pound, and intake orifice area; but I gave up when they got within a hundred feet. At this range I could hear their guts rumbling.

Big Boy scented me first. His head went up; a cold reptilian eye the color of a bucket of blood rolled my way. He snorted. He drooled-about a gallon. His mouth opened, and I saw rows of snow-white teeth, some of which waggled, loose, ready to shed. He steam-whistled and started my way. It was decision time, and I didn"t linger.

I took a final breath of humid beach air, a last look at the bright, brutal view of sea and sand, the high, empty, impersonal sky, and the jolly monster shape looming up against it. Then I played the tune on the console set in my Jaw.

The scene twisted, slid sideways and dissolved into the painless blow of a silent club, while I looped the loop through a universe-sized Klein bottle- Total darkness and a roar of sound like Niagara Falls going over me in a barrel.

8.

For a few seconds I lay absolutely still, taking a swift inventory of my existence. I seemed to be all present, organized pretty much as usual, aches, itches and all. The torrent of sound went on, getting no louder or softer; the blackness failed to fade. It seemed pretty clear that while I had left where I was, I hadn"t arrived much of anywhere.

The rulebook said that in a case of transfer malfunction to remain immobile and await retrieval; but in this case that might take quite a while. Also, there was the datum that no one had ever lived to report a jump malfunction, which suggested that possibly the rulebook was wrong. I tried to breathe, and nothing happened. That decided me.

I got to my feet and took a step and emerged as through a curtain into silence and a strange blackish light, shot through with little points of dazzling brilliance, like what you see just before you faint from loss of blood. But before I could put my head between my knees, the dazzle faded and I was looking at the jump room of a regulation Nexx Staging Station. And I could breathe.

I did that for a few moments, then turned and looked at the curtain I had come through. It was a perfectly ordinary wall of concrete and beryl steel, to my knowledge two meters thick.

Maybe the sound I had heard was the whizzing of molecules of dense metal interpenetrating with my own hundred and eighty pounds of impure water.

That was a phenomenon I"d have to let ride until later. More pressing business called for my attention first-such as finding the station chief and reporting in on the destruction of Station Ninety-nine by surprise attack.

It took me ten minutes to check every room on operations level. n.o.body was home. The same for the R and R complex. Likewise the equipment division and the power chamber.

The core sink was drawing normal power, the charge was up on the transmitter plates, the green lights were on all across the panels; but nothing was tapping the station for so much as a microerg.

Which was impossible.

The links that tied a staging station to Nexx Central and in turn monitored the activities of the personnel operating out of the station always drew at least a trickle of carrier power. They had to; as long as the system existed, a no-drain condition was impossible anywhere in normal s.p.a.ce-time.