"No!" she said. She clutched my wrist, then withdrew her too-hasty hand. This time, she did blush. "Please, do go on."

I did. By the time we reached the southern sh.o.r.e of the Firth of Forth, her textbook was covered with delighted scribbles linking facts at last, and her face with astonished smiles and happy frowns at the results.

I was about to part with her, at the station - which is called simply Edinburgh Central, Walter Scott in this world having remained an advocate at the Bar - smug in my Improving zeal, when she caught my elbow.

"Mr Jones," she said, "may I presume upon our acquaintance to ask you to escort me to my destination? It is in the West Port, and - " She looked away.

"And the Gra.s.smarket is notorious for footpads, and you cannot afford a cab? Don"t worry, Miss d.y.k.es. I can"t afford one either. Let us walk together."

I carried her luggage. It was pathetically light.

"Mr Jones," she enquired anxiously as we emerged from the rear of the station on to Market Street and caught our first stagnant whiff of the Nor Loch, "I see you carry no weapon."

"I need none," I a.s.sured her. "I am an adept in the martial arts of the East."

She laughed. "Ancient arts are no match for a good pistol, sir, but I still trust in your protection."

Across the Royal Mile, down St Mary"s Street into the Cowgate, then along beneath the North Bridge and Charles IV Bridge towards the Gra.s.smarket. High, dank walls like cliff-faces dripped. Opium dens wafted their dark allure. Gypsy fiddles enlivened the air around hostelries. Homeward cars and velocipedes splashed through the noxious puddles. After the Cowgate, the Gra.s.smarket was respectability itself, even with its tinker stalls, beggar families, skulking footpads, stilt-walking clowns, and carousing students of medicine, divinity and law. The flag of the Three Kingdoms, aflutter in the evening breeze, could be glimpsed over the Castle which, like its Rock, straddles history st.u.r.dy and aloof with only its flags changing, above the Gra.s.smarket"s seething pool of probabilities.

Out of that seething pool stepped my pursuer. Two metres in front of us, and no one in between. If I hadn"t recognized his face, the levelled thing in his hand would have identified him surely enough. In this world, it might have seemed no more than a glittering toy, but Mary Ann divined its sinister import in an instant. Or perhaps she just reacted to my start. She clutched my upper arm with both hands. From the point of view of one about to draw on the martial arts of the East, this was not a welcome move, however pleasing it might have been under other circ.u.mstances.

After a split second of bafflement, I realized that my pursuer must have stayed in the GBR, guessed - or been leaked - my destination and blithely taken the faster train of that more advanced world, then sidestepped to this world of Tairlidhe"s victory to await me. How he"d found out that this was the world to which I"d fled to evade him, I didn"t care to guess. Infiltration and defection are permanent possibilities, across all probabilities.

I had no choice. I sidestepped, back to the GBR. I may have hoped my pursuer wouldn"t expect that, but in all honesty it was a reflex.

I had never before sidestepped with someone holding on to me. I was almost as surprised as Mary Ann to find us still together, in a different Gra.s.smarket.

"What is this?" she cried, gazing around bewildered at the suddenly airier, cleaner, brighter and even noisier s.p.a.ce of the plaza. She let go off me, and took a swift pace or two back and looked at me with suspicion and dread. "What arts of the East have you used, Mr Jones? Sorcery? Illusion?"

"Not these, I fear," I said. "This is real. It is a different reality than that to which you are accustomed - one in which history took a different turn, centuries ago."

She seemed to grasp the concept at once.

"Are there many such?"

"An infinite number," I told her.

"But how marvellous! And yet how obvious, that the Creator"s infinity should be reflected in His creations!"

"That"s one way of looking at it," I allowed.

Mary Ann looked around again, more calmly now, though I could see her quivering.

"I see this is a history in which the Covenanters" memory is honoured," she said. She pointed to one of a trio of statues. "I recognize that visage, of Richard Cameron. But who are the others?"

"They will mean nothing to you," I said.

"I want to see them, all the same."

She was intrigued by the pedestrian crossing, and impressed by the vehicles, tinny and two-stroke though they were. I nudged her to stop her staring at women with bare heads and short skirts. We stopped beneath the statues.

The stern man in the homburg, with upraised, didactic, forefinger: "John Maclean," she read from the plinth. "A preacher, was he?"

"In a manner of speaking," I said. "And in his manner of public speech, by all accounts."

The man in the short coat, with gla.s.ses and pipe - and, Scotland being Scotland in all manifestations, with a traffic cone on his head: "And "Harold Wilson, martyr of British democracy"?" She recoiled almost, frowning. "A democrat? A radical?"

"Not precisely," I said, looking around distractedly. "It would take too long to explain. That man who confronted us -he may catch up at any moment. I must go."

"What about me, Mr Jones?" Mary Ann said.

"I"m sorry," I said, still looking about. "I can"t take you with me. It"s far too dangerous. You"ll be safe here for now." My gaze alighted on a tall concrete building, from which hung a banner with a jowly, frowning, face and the letters "GB". I pointed.

"Remove your bonnet," I said. "It"s not customary here. Your dress will pa.s.s. Go to that building, ask for the Women"s Inst.i.tute, and say that you have just arrived from London, penniless. Say nothing of where you really come from, lest you be consigned to a lunatic asylum. You will be made welcome, and given employment. Learn what you can in this world, and as soon as possible I"ll take you back to yours."

"But - "

Out of the corner of my eye, I saw my pursuer emerge from the pub called The Last Drop, and peer around.

"Goodbye, Miss d.y.k.es," I said.

I handed her the oranges - they were for here, after all, where they were scarce - and sidestepped as far as I"d ever dared in a single jump.

4. Storm Constantinople!

And fell briefly into a world of Latin buzz and blazing neon, of fairy lights suspended on nothing above a gra.s.sy park, on which robe-clad dark-skinned people strolled beneath a Rock with no Castle, and with an evening sky alight with the artificial constellations of celestial cities in orbit overhead. I sprinted across the sward, towards where the King"s Stables Road wouldn"t be. I"d never been in this probability, but I recognized it by report: this is the one where Spartacus won, slavery fell, capitalism rose, and the Romans reached the Moon in about 500 (Not) AD and Alpha Centauri a century or two later . . .

I leaped a stream that in most other worlds had long since been a sewer, sidestepped in mid-air, in a familiar but much less hopeful direction, and came down with a skid and a thud on dust and ash. I stumbled, flailing, and trod on a circle of glowing embers which I as quickly jumped out of, scattering more ash.

"Oi!" someone shouted. It must have been his fire.

"Sorry!" over my shoulder. Then I ran without looking back. Around me the early evening was lit only by scattered small fires, some of them behind the window-s.p.a.ces of what buildings remained standing. Gra.s.s and weeds poked through the crazed tarmac under my feet. A few metres in front of me, a random leaf of gra.s.s or sc.r.a.p of paper caught fire. I threw myself forward, hitting the ground with a pain I wouldn"t feel for minutes. I side-stepped into an adjacent probability, as one might roll on the ground, got up and ran on.

The Improver base in this Edinburgh lies beneath where a multi-storey park had been, close to the unaltered Castle Rock. I reached the door - saw a red bead on the wall - flinched aside - keyed the code in the lock - dived through.

I stood up in low fluorescent lighting, pale corridors. I suspected my pursuer would be after me. I rang the alarm. Two guards were ready for him when he slipped into our s.p.a.ce from a probability where the car park"s floors hadn"t pancaked in the blast from Rosyth. His capture took only a moment: a hiss of gas, a thrown net, the laser pistol knocked from his fingers.

The guards tied him in the net to a chair. I tried to interrogate him, before the effects of the gas wore off and he gathered his wits enough to sidestep.

"Why are you after me?"

His head jerked, his eyes rolled, his tongue lolled. "Isn"t it obvious? You were on a mission to undermine the GBR!"

"What"s that to you?" I said. "To Conservers, that regime must be an abomination anyway - radical, revolutionary even - isn"t that everything you"re against?"

"No, no." He struggled to focus his eyes and control his drool. "It"s a rare marvel. A socialist state that works, that has survived the fall of Communism, because of the computerized planning developed at Strathclyde from the ideas of Kantorovich and Neurath. You have no idea, do you, where that might lead? Nor do we, but we want to find out."

"Well," I said, "sorry about that, old boy, very interesting no doubt, but I"m f.u.c.ked if my relatives will suffer in this Caledonian Cuba a second longer than they have to."

He inhaled snot. "f.u.c.k you."

I could see I wouldn"t get much more out of him, so I whiled the minutes before he recovered enough to slip away by taunting him with what I"d done on the train. He looked at me with horror and loathing.

"You introduced Darwin to that world?"

"Who?" I said. "Wallace"s theory of natural selection - that"s what I outlined."

He thrashed in the net. "Whoever. You know what you may have done, if that young woman should be the one who convinces that world that evolution happened? Some day, perhaps many years hence, in some backwater of an Eastern empire, a young man - an Orthodox seminarian in Georgia, perhaps - will read her work, lose his faith, and go on to lead a b.l.o.o.d.y revolution - "

" - which will happen anyway, in one or other of these s.h.i.t-holes," I said. "We"re working on that problem."

"I wish you luck," he said drily. He was coming to, now, almost ready to vanish before our eyes.

"And what about this world?" I demanded. "This post-atomic horror? Would you have us leave it too?"

"Yes," he said. "To see what comes of it. Let it be."

And he went. The net slumped to the chair. I looked at the guards, shrugged.

"C"est la vie," one of them said. "Come on, you need a coffee. And some bandages."

I followed them to the first-aid station, then to the canteen. As I sipped hot black coffee, I found myself gazing idly at the room"s walls, which were papered with old newspaper and magazine pages, saved from ruins. A particularly striking front page of the Daily Mirror, from May 1968, showed four longhaired young people in white T-shirts with a big black cross, which in a colour picture would have been red. The caption identified the youths as Andreas Baader, Ulrike Meinhof, Bernadette Devlin and Danny Cohn-Bendit. They stood on a platform in front of a huge crowd, the wind blowing in their hair, AK-47s in their uplifted hands, and behind them the skyline of Istanbul. The city in whose streets they would, a few hours later, fall to a hail of machine-gun bullets - along with a shocking proportion of the youthful crowd.

What good could come, I thought, of probability as crazy as this? One in which Pope Paul VI had responded to the Israeli victory in the Six-Day War of 1967 by claiming Palestine again for the Church, and urged the youth of Europe on a crusade to win it back? A crusade that had ended with an a.s.sault on Istanbul, a city too stubborn to let the human tide through? And where the ma.s.sacre had sparked an international incident that had escalated to an all-out thermonuclear exchange?

While worlds like that - and worse - exist, I remain an Improver.

I caught up with Mary Ann d.y.k.es a few weeks later, on another of my jaunts to the Republic. I"d made my dead-letter drops for the dissidents, I had a spare few hours, and I sought her out. I found her working in a women"s refugee centre, giving, as she put it, something back for the help she"d been given. Her hair was trimmed, her skirt short, her cheeks pink, her habits unladylike. I spoke to her outside, as she took a cigarette break on the street. She"d applied for a place at Glasgow, to study zoology.

"I can take you back," I told her. "Back to your own world, where the knowledge you"ve picked up can make you famous, and rich."

She sucked hard on her cigarette and looked at me as if I were crazy. She waved a hand at the street, all ruts and litter and Party posters flapping in the breeze and GB"s face and Straw"s surveillance cameras everywhere.

"Why?" she demanded. "I like it here."

There"s pleasing some people, that"s the trouble.

The Wandering Christian.

Eugene Byrne & Kim Newman.

"I"m dying," said the madman next to him.

"So," Absalom grunted, feeling the arrowhead shift against his ribs, "there"s a lot of that about."

"No," said the madman, eyes like candle flames, "I"m really dying."

Absalom coughed, bringing up blood. The arrow had dimpled one of his lungs, and he was slowly drowning, he supposed, his blood filling up his lungs. He knew more about doctoring than the barber-surgeons who occasionally came round to see what they could do for the wounded. As a soldier, he was more than familiar with the many ways a man could die.

He tried to remember whether he had seen the madman before, up on the walls of Rome, maybe defending one of the gates. Now, he was bearded and scrawny, his hands pressed on the yellow rag he held to his liver, trying to keep his insides in. His armour and weapons were long gone, pa.s.sed on to a healthier defender.

"It"s the end of time," he said. "What date is it?"

"The second day of Tammuz."

"No," the madman coughed, "the year? I"ve forgotten."

Absalom knew his One True Testament. "It"s 4759," he said. "4759 years since the creation of the world. It"s not the end of time at all. The Messiah has not come."

The madman grimaced, painfully. Absalom realized he really was mad. Twenty-two years of soldiering, and he would die a forgotten hero with only a lunatic for company.

"Even if Rome falls, it will not be the end of time. The Chosen People will endure."

The madman began to choke, and Absalom thought he was about to pa.s.s away, but his coughs changed, turned to bitter laughter. He was beyond pain, beyond everything.

"The Chosen People," he said, "the Chosen People ..."

Outside the walls, the Persians were gathered, half-heartedly building their earthen ramps to the edge of the city, barely bothering to launch attacks with their huge wooden siege-towers any more. They were catapulting rocks and corpses into the city, and firing rains of arrows, but mainly they waited for starvation and disease to do their job for them. At first, Shah Yzdkrt, known as Yzdkrt the Flayer, had decreed that all Gentiles would be allowed to pa.s.s unharmed through the besieging ranks and, after paying a small tribute, be allowed on their way. But the rumour was that those citizens foolhardy enough to believe him had been meekly led to a glade on the Tevere and slaughtered, their bodies dumped into the river in an attempt to poison the city"s water supply. Two months ago, rabbi Judah, a good and humble merchant well known for his charitable works, was sent out to parley with the Persians, taking with him gifts for Yzdkrt and a message of peace from the Emperor. Yzdkrt had him slowly stripped of his skin, and his hide was stretched out on the ground before the main gate as a reminder to the besieged Romans of the fate the Shah had set aside for them all.

Governor David Cohen was ruthlessly enforcing siege regulations on the populace, military and civilian. Soldiers were on half-rations, all others on quarter-rations. Absalom heard that anyone who used water for washing was being put to death. Certainly, no one had offered to clean his wounds, with the result that even if he didn"t drown he"d be eaten up by the mange spreading from the cuts on his body. The wounded were being stacked up in the catacombs, out of sight, but it was impossible to silence their screams. When he had been on patrol up above, everyone had been spooked by the groans coming from under the earth. Now he was with the groaners, and he thought he had a foretaste of h.e.l.l. There were a few lamps, but it was mainly gloomy, and some straw had been spread to lie on, but it was filthy with blood and s.h.i.t. Latrines had been dug, but most of the wounded were unable to get to them without help, and there was no one to help. The tunnels were trickling with sewage.

A few of the more zealous or compa.s.sionate rabbis left their other trades or duties and ventured into the catacombs to comfort the dying. Absalom could always hear the low mumble of the kaddish under the screaming.

Rumours were the only entertainment the dying had. Absalom received the rumours from Isaac bar-Samuel to his left and pa.s.sed them on to the madman as they came his way. It was rumoured that Governor Cohen was expecting an army of relief directly from the North, led by the Emperor in person; that the plague raging in the city had spread to the Persians, and that Yzdkrt himself had succ.u.mbed; that the men of Rome, no matter how young or old, were used up, and that the women were being impressed to bear arms against the Zoroastrian unbeliever. The madman took it all lightly, laughing as the yellow stain spread up his side.

The rats would have been a problem, only Governor Cohen had organized gangs of children to hunt them for food. The shochets were setting aside the dictates of kashrut and learning to make do with rodent meat. In the catacombs, where any animal that got within reach of a man deserved the swift death it inevitably got, even the niceties of butchering were being ignored. Raw ratmeat was tough, but chewing something helped lessen the pain.

A new rumour came down from Isaac. Above, it was noontime, but the sky was dark. The sun had been blotted out, and a peculiar sign was visible in the sky, an upright cross, like the skeleton of a kite, stood out in fire against the black. The rabbis and scholars were arguing its significance, and no one could tell whether the sign was meant for the Chosen People inside the walls or the infidel beyond.

Absalom told the madman, and, for the first time, got a reaction out of him.

"It has come. It is time. One thousand years."

"What"s the babbling idiot talking about?" Isaac asked.

Absalom shrugged, feeling a stabbing under his arm as his broken bones shifted.

"I don"t know. He"s mad."