Continued from here.

CHAPTER THREE

"Welch put you up to this, didn't he?" Stone said. "The slick son of a bitch brought you through the mirror because he thought you might flush out your father."

"It isn't like that at all," Linda Waverly said, and started the taxi and pulled away from the curb. "When my father shot that woman, I was already working here. In this sheaf, in New York. I was taken off my job and grilled by Ralph Kohler's people for six hours straight. They were going to send me home, but David Welch persuaded them to let me help out."

"Welch likes to play games, Linda. He's using you."

"There's a good chance my father will try to make contact with me if I'm out on the street in plain view. What's wrong with that?"

"You can let me out right here. Then you can turn this taxi around, find David Welch, and tell him that I think he's crazy." Stone tried the door; it was locked. He rapped on the plastic partition and said, "That wasn't a suggestion, by the way. Stop right here."

Linda looked at him in the rearview mirror with cool defiance. "What are you going to do if I don't? Shoot me?"

Stone felt a little pang of guilt, and wondered if Tom had broken one of the golden rules of clandestine service and told his daughter about what had happened when SWIFT SWORD had fallen apart. "I came here because your father asked for me. Because I'm his friend, and because he saved my life once upon a time, and I still owe him. I don't know why he's been doing what he's doing, but I do know that you don't want to get caught up in it."

Linda said, "I thought my father died three years ago, Mr. Stone. Now I know he didn't, I want to help find him and bring him in safe and sound." "You're being used, Linda."

"We're both of us being used, Mr. Stone. Maybe we can figure out how to make the best of it."

Stone had to admit that it was a good point. Linda definitely had a stubborn streak a mile wide, just like her father, but she also appeared to be sensible and levelheaded, and she had been working right here. She had local knowledge. Maybe he could turn this around, Stone thought. Pay back Welch in his own coin. He leaned forward and spoke into the cluster of holes drilled in the partition. "You can drive me to the scene. When I've finished

there, we can try to work something out."

"You won't regret it, Mr. Stone."

"And you can slow down, too. Before we get a ticket."

"You don't like my driving?"

"I guess it has been a long time since I was in a New York taxi. A long time since I last saw you, too. What were you doing, before David Welch brought you into this thing? I take it you're working for the Company now."

"I'm part of a team that's liaising with the local FBI, trying to break up criminal gangs that are smuggling deserters out of the country. The desertion rate among our troops is three percent and rising. A few want to find their doppels, or the doppels of their wives or sweethearts, but most of them want to get to Canada. Canada is neutral in this sheaf. Once they're over the border, they're gone. The gangs help them get across, and then squeeze them for interest payments on the fee."

"So you're a field officer, just like your father."

"Actually, at the moment, I'm more on the analytical side of things. I was seconded from DI to help run a datamanagement system-computer work, basically. But I get to sit in on interviews with suspects, and I've been on a couple of raids, too."

"How do you like it, out in the field?"

"I was working with the forensic crew both times. I didn't come in until after the assault teams had taken out the bad guys. But it was still a buzz."

"I guess it must be," Stone said, remembering his first field actions. How it had all seemed like good clean fun until he'd had to shoot someone.

"I majored in anthropology at NYU before I joined the Company," Linda said. "This is my first time through the mirror, and I end up back in New York. It's different, but not that different. There's the aftermath of the war, of course, and the Dodgers and the Giants are still here, they didn't move to the West Coast. But it isn't like it's a foreign country. Apart from downtown, the streets are more or less the same. They have NYU, they have guys playing chess in Washington Square, they have yellow taxis and hot dog carts. . . . It reminds me of the time I went to Arizona with Mom and Dad. I was fourteen, they'd just got back together after their first big bustup, and we took a trip to Arizona for a good oldfashioned family vacation. We visited with my aunt, my mother's sister, in Phoenix. We drove all around. We saw the Grand Canyon. We saw Sedona. You want to talk about another world, there it is. Sedona. All those red rocks, it's like nowhere else on Earth. Like Mars.

But it was still America, all the same. You travel a thousand miles to somewhere completely different, and you find the same TV shows, Coke, McDonald's. . . ."

"There are all kinds of different Americas, but they're all America."

"One nation under many skies. I remember seeing a man in a restaurant in Arizona who kept on his hat while he was eating. An expensive one, white, with a strip of snakeskin around the crown. He had these cowboy boots with little pointy toes, too. That was different, watching a man dressed like a cowboy spoon soup under his hat brim." Right in front of them, a truck swerved across two lanes. Linda hit her horn. "Army drivers, I swear none of them have licences."

Stone remembered the last time he'd seen Linda. It had been at one of Tom's parties. A little girl in a black bathing suit, screaming with laughter as she ran through the spray of the sprinklers in the vegetable patch behind the house. She'd been, what, ten or eleven. . . . A few weeks after that party, Stone had gone through the mirror again, had spent a couple of years working on a clandestine operation to overthrow the government in the American Bund sheaf. Toward the end, with everything lined up and the final stage of the operation about to kick off, Tom had turned up to help out, and the first thing he'd said to Stone was that he'd split up with his wife. He'd gone back to her that time, the marriage had staggered on for a few more years, but there had been no more barbecues at the little house in the woods. Stone hadn't seen Linda Waverly since that party, and now here she was, driving him toward the scene of a double murder committed by her father. It was the kind of thing, he thought, that made a man feel the years in his bones.

Linda broke the silence that had grown between them. "Did he really save your life, once upon a time?"

"He was given a medal for it."

"The Intelligence Star?"

"That's the one."

"I went to the ceremony, but he never explained what he'd done. He liked to tell tall stories about travelling in other sheafs, but he never once talked about his work. His real work, I mean, not the cover stories. Even after I joined the Company, he used to say that if he ever told me anything about his actions, he'd have to kill me afterward. With that look that meant you could never tell if he was joking or not."

"I remember that look."

"Of course, I picked up a few bits and pieces during my training. Some of the stuff you oldschool guys were involved in is in the text books, and one of my instructors knew my father. I get the impression he was something of a rogue operator."

"He always had a reason for everything he did. And I'm sure there has to be a reason for this."

Stone wasn't about to tell her that her father might have sold out, or gone bugeyed crazy.

"There's a rumour that the Company has an internal situation. That there's been a purge, there was some kind of problem at White Sands . . . ?"

"I'm retired, Linda. I'm no longer plugged into the rumour circuit."

"I thought Mr. Welch might have told you something."

"Welch likes to play games, remember? Withholding information or giving out partial information is part of it. Who was purged?"

"There aren't any hard facts, but something's definitely going on. Where I work, a couple of people due to go on leave have had their leave cancelled, and a couple more haven't come back from leave-"

"In case they're infected with rumours."

"There's been a hitch in communications through the mirror, too. Also, the station chief gave us a little pep talk a few days ago. Something's going on for sure, and I can't help thinking that it might have something to do with whatever it is my father has gotten himself into."

North Meadow swung by. The sky was growing dark beyond a line of trees. A chain of streetlights flickered on one by one. Stone thought of the whitewashed cabin set on the ridge above the wild, untravelled Hudson, and wondered what Susan was doing at that precise moment, several miles and two sheaves away. All they shared now was time. Whenever history split, time rolled on at the same speed, one second per second, in the two daughter sheaves. In every version of America, in every known and unknown sheaf, it was September 15, 1984, six thirtytwo p.m. Stone thought of Susan moving about in the kitchen where Petey's crayon drawings were tacked to the plank wall by the sash window, steam rising from a pot on the woodburning stove, the cozy, familiar domestic clatter, and felt a sudden yearning ache.

He'd met Susan's husband, Jake Nichols, in the American Bund sheaf some ten years ago. Stone and his fellow Special Ops officers had helped to incite a revolution; Jake had been part of the peacekeeping force that had come in immediately afterward. Stone had hit it off from the start with straighttalking, cando Lieutenant Nichols, and had been one of the first to visit Jake in the VA hospital a year later, after Jake had lost two fingers on his left hand, the calf muscle of his left leg, and five feet of his small intestine to a roadside bomb. Afterward, Jake walked with a limp and had to take painkillers and steroids twice a day, but he didn't let his disabilities slow him down. He quit the army and went to work for the American Red Cross, which was where he met and married Susan. Stone was the best man at their wedding.

When Susan became pregnant, Jake invoked the right, granted by the Veterans' Bill to every honourably discharged member of the armed forces, to move to a wild sheaf. He and Susan bought a farm in the First Foot sheaf from a lottery winner who'd had enough of the frontier life, and Stone followed them there after he resigned from the Company. He paid his community dues by working on the railroad, then took a job as a guide for the Nichols' hunting outfit, leading rich clients through the pine forests and marshes to the west of the Hudson in search of mastodon, giant sloths, sabretoothed cats, and other megafaunal species that in the absence of native human beings still flourished there. Susan handled the paperwork and Jake had forgotten more about hunting than Stone would ever learn, but they insisted on making Stone an equal partner in the business.

After Jake's fatal accident out on the ice, Stone did all he could to help Susan keep both the farm and the hunting business going, and when the snows melted and the growing season began, with fields to plough and crops to plant and tend, it seemed sensible to leave the little cabin he'd built near the shore of the East River and live on the farm. Just for the summer, he and Susan agreed. Just for the summer, and then for the harvest. Their discussions about the future were strictly practical. They talked about dismantling Stone's cabin and rebuilding it closer to the farm, about hiring help, about how they could improve the hunting business. They talked about everything except the mutual feeling that grew between them that summer, furtive and patient and strong as a flower pushing through the concrete slabs of a sidewalk. There were moments-one hot, still evening when they sat together and watched the sun set over the Hudson, the day they went fishing for striped bass in Stone's little boat, a long ramble through the woods, picking mushrooms-when Stone had been ready to confess to Susan that he'd fallen in love with her. But it was still too soon after Jake's death. It felt too much like the low subterfuges and betrayals of adultery.

Now, remembering what he and Susan had said to each other in the barn and what had hung unspoken in the air, Stone knew that they would have to sit down and have themselves a hearttoheart talk when he returned to New Amsterdam. It was time he bit the bullet.

The taxi had stopped at a red light at the western border of the park. Stone told Linda Waverly to take a right.

"Quicker if I go straight across."

Stone was looking out of the taxi's rear window at the vehicles in line behind it. "Go right, then take Duke Ellington Boulevard, or whatever they call it here."

"They call it Duke Ellington Boulevard." The light changed. Linda turned right. "If the guys following us know where we're going, what's the point of trying to lose them?"

"I want to show them that we know they're there," Stone said.

When Linda turned the taxi onto Duke Ellington Boulevard, he saw the sedan that had followed them through Central Park make the same manouevre.

"You see it?" Linda said. "The white Ford four cars back?"

"I see it."

"He took over from a red Chrysler on Madison and East EightyFifth."

"I guess I'm out of practice," Stone said.

This girl who'd once scampered about in summer twilight wearing a white taffeta dress with fairy wings pinned to the back calmly telling him about a switch he hadn't seen.

"Who do you think they are?" she said. "Locals, or Company?"

"Does it matter?"

Up in the low hundreds, things didn't look that different from Stone's memories of New York in the Real. A little less neon, the storefronts shabby but homelier. Not as many highrise apartment blocks, that was for sure. Most of the pedestrians were civilians, and there seemed to be more white people here than in the Real. They were heading home, buying fruit and bottled water in superettes, walking their dogs. A fat man in an undershirt stood at the doorway of a drycleaning place, smoking a cigar with the placid, absolute authority of the Emperor of all Time and Space. Then the taxi turned onto Riverside Drive, with brownstones and taller apartment buildings facing the long park, and glimpses of the river through the trees.

This sheaf's doppel of Eileen Barrie must have been doing well: she owned a turnofthecentury brownstone right on Riverside Drive, a few blocks south of her workplace at Columbia University. Sawhorses blocked off the sidewalk and a uniformed cop stood by the railings at the bottom of the steps up to the front door. Most of the windows were broken, and smoke had blackened their lintels.

Stone told Linda to wait in the taxi. She said she didn't mind, she'd already scoped the scene.

"Welch brought you here, I bet."

He'd shown her what her father had done, Stone thought, and put her on the spot, in plain sight. David Welch and his insincere charm, his smoke and mirrors, his sly little tricks.

Linda said, "I can walk you through it, show you how it went down."

"I read the report. Stay there while I figure a few things out. It shouldn't take long."

Stone didn't want to discuss the murders with Linda and talk about the different ways her father had killed six doppels of the same woman. Also, he wanted her to sit right in front of the house. If Tom Waverly was hiding close by, she might draw him out or at least make him careless. When it came down to it, Stone thought as he swung out of the taxi, he wasn't any better than Welch.

He showed his ID to the cop, borrowed the man's flashlight and the keys to the house, and told him to go find a cup of coffee. The splintered front door was chained and padlocked, and sashed with yellow crimescene tape. There were spray patterns of blood on its green paint, spots and spatters of blood on the columns on either side, and plenty of smears and boot prints left by police, paramedics, and firefighters who'd stepped in pools of blood that were now dried to flaky crusts on the steps.

According to the preliminary report in the file Welch had given Stone, the hit had happened just before dawn. Tom Waverly had climbed onto the roof, removed the protective mesh from the top of one of the disused chimneys, and lowered into it a flexible plastic tube containing a mix of gasoline and liquid soap. When this homemade napalm had ignited, probably sparked by a timed charge, it had blown out most of the windows and started a fire in the kitchen at the rear of the house. Nathan Tate had brought Eileen Barrie out the front, sandwiched between two police from the mayor's protection squad, and that had been where they'd both died, shot by a .308 rifle from a position across the road in Riverside Park. Nathan Tate had been right in front of Eileen Barrie when he'd been shot. And before he'd hit the ground, before the police officers had cleared their weapons from their holsters, Eileen Barrie had been shot too, once in the chest, once in the head, and then a burst of fire from a machine pistol had sent everyone diving for cover, and two smoke grenades had ignited in the middle of the street. It had been all over in less than a minute. Quick, brutal, thoroughly planned, calmly executed.

Stone crossed the street and stepped into the park. Trees sloped down toward the river. His new, thinsoled shoes slipped on leaf mulch. He could hear the warm wind moving through the trees, the hum of traffic on the Hudson Parkway.

Twenty minutes before the bomb had gone off, Tom Waverly had knifed one of the uniformed cops who had been patrolling the park, the mayor's nephew, and dragged his body under a laurel bush. And then he'd taken up his position in a tall oak that was now ringed off by police tape, whiling away the time before his napalm bomb went off by whittling a message into the bark of the tree.

I'll talk to Stone.

The undergrowth around the tree had been trampled flat. Tom Waverly had taken the machine pistol with him, but the boltaction Winchester .308 had been found at the foot of the tree, and the rope he'd used to slide to the ground after the hit was still in place.

Stone hooked his suit jacket on a branch and used the rope to climb as high as he could. Splintered rips in the tree trunk suggested that Tom had worn spiked overshoes to help him climb through the canopy, almost to the top of the tree. Stone couldn't get that high, but thirty feet up he had a pretty good view of the brownstone. The yellow taxi was parked right in front, Linda Waverly dimly visible through the side window, sitting there like a target. Stone realised that he should have asked her if she was carrying a pistol before he left her there, just in case Tom took the bait-but even if she was armed, she was hardly likely to draw down on her own father.

He straddled a branch and thought about angles, figured that if he climbed another twenty feet he would have been able to look over the top of the moving truck Nathan Tate had used to screen the front door of the brownstone from the street. Tom must have scoped out the scene sometime before he made the hit. He'd brought rope and spiked overshoes because he'd known that he would have had to climb this high to make the hit. And he'd known that there was a way out through the back yard, so he'd set the fire in the kitchen to force everyone in the house out the front door. Stone smiled. Tom might have gone crazy, but he could still set up a hit with meticulous precision. Leave anything to chance, he used to say, and you'll most likely end up in a box like Schrödinger's cat, wondering when you're going to start smelling almonds.

Dick Knightly's cowboy angels had learnt about the fundamental principles of the Many Worlds theory during their training. Their physics instructor, Fred Lehman, introduced the concept with Schrödinger's "ridiculous case," a thought experiment designed to challenge the assertion that measurement forced a quantum system to adopt a specific state, and any observer making measurements could not be isolated from the system he observed. In Schrödinger's thought experiment, a cat was placed in a box equipped with a flask of cyanide gas, a mechanism that would break the flask if a detector was triggered by the random decay of an atom, and a source of radioactivity so weak that there was only a fifty percent chance that a single atom would decay in any given hour. The cat and the mechanism were sealed inside the box, and the experiment ended after exactly an hour, when the box was opened again.

"Schrödinger's question was this," Fred Lehman said. "With a fifty percent chance that an atom has decayed and triggered the mechanism that releases the cyanide, what's the state of the cat immediately before the box is opened?"

Tom Waverly raised his hand, saying that he had a question of his own. What, he wanted to know, did this Schrödinger guy have against cats?

This was in the lecture theatre at Brookhaven. Fifteen young men and one young woman were scattered across tiers of seats, some assiduously taking notes, some hopelessly lost, all of them feeling the same electric thrill of participating in something tremendously secret and important. Tom Waverly was sprawled in a seat in the front row, his arms stretched across the backs of the seats to either side, smiling while he waited for Fred Lehman's answer.

"We're not talking about a real cat in a real experiment," the physicist said. "The cat is a metaphor Schrödinger used to ridicule the suggestion that quantum theory could be used to make a complete description of physical reality. He claimed that before the box is opened, the cat must be in some indeterminate state, half dead, half alive. Since no living creature can be alive and dead at the same time, there must be something wrong with quantum theory."

"Of course it can't be a real experiment," Tom Waverly said. Looking around, taking his time, building to his punchline. "I mean, have you ever tried to get a cat inside a box?"

In the warm dark, high above the ground in the branches of the oak tree, Stone smiled, remembering that Fred Lehman had waited out the laughter before explaining that the premise on which the thought experiment had been based was wrong, that the cat in the unopened box did not exist an indeterminate state, neither wholly alive nor wholly dead, as Schrödinger had asserted. Instead, the experiment caused the state of the observer to split into two-and it didn't matter if the observer was the experimenter, the cat, or the radiation detector, as long as something or someone took a measurement that forced the quantum system of cat and box and cyanide apparatus to adopt a definite state. In one universe the observer opened the box and discovered a live cat; in the other, the box contained a corpse.

And this happened with every choice we ever make, Fred Lehman had told his class. In most cases the split was trivial and the two sibling universes quickly recombined. But if the observation caused a change big enough to affect other observers, recombination was delayed, and more and more differences accumulated in the states of the sibling universes until the split became permanent. A single probability sheaf split into two; history went in two different directions. In one the cat was alive; in the other, it was dead. In one, Khrushchev was assassinated and the Soviet generals ordered an atomic strike against the United States; in another, the assassination attempt failed or was stillborn, and Khrushchev withdrew the Soviet missiles and battlefield atomic weapons from Cuba. Each sheaf was woven from billions of closely related microhistories that branched and recombined and branched again as billions of observers made their trivial choices. But although most microhistories recombined almost immediately, a significant number did not, and in a few of those the split eventually became permanent.

Tom Waverly had loved the weirdness of quantum theory, but on a job he'd always done everything he could to avoid the dichotomous fate of Schrödinger's cat, planning his hits to the last detail. It was pure bad luck that the cop had stumbled across him when he was moving into position. If he had shot only Eileen Barrie and Nathan Tate, the locals would have requested that a couple of NYPD murder detectives liaise with the Company team, purely as a formality, and left it at that. But Tom had killed a cop, the cop had been the mayor's nephew, and now every one of New York's finest was looking for him. Because one of their own had been murdered, they had permission to shoot on sight, and they were ready and willing to take care of business.

I'll talk to Stone. But where, and when? Stone knew that he would have to think hard and fast, and hope for a lot of good luck, if he was going to catch up with Tom before the locals did.

He slid down the rope, put on his jacket, and walked back to the edge of the park and stood there for a few moments, looking at Eileen Barrie's brownstone and the identical brownstones on either side, their bow windows, the balustrades that ran along the edges of their flat roofs. He slapped a lone, late mosquito and walked across the street. When he reached the taxi, Linda cranked down her window and asked if he had found anything.

"The report said that he got onto the roof of the house from one of the neighbouring brownstones."

"The one on the right. He got in through the back, picked the lock of the fire door in the basement, then picked the lock of the access door to the roof. The forensic team found fresh scratches on both of them. You think they missed something?"

"I'm wondering why he didn't stay up on the roof after he planted the napalm. He had an easy shot of the front door from across the street, but he had to evade police patrols to get into position. And in fact he didn't evade them-he ran into that cop. If he'd stayed up on the roof, the shot would have been harder, but he wouldn't have had to take the risk of moving into the park."

"He couldn't stay up there because there were men posted on the roof of Dr. Barrie's brownstone."

"There were? How many?"

It hadn't been in the report.

"Two sharpshooters. They were watching the back yards and the roofs on either side."

"Were they in position all the time?"

"Only when Dr. Barrie was at home. When she went to work, a couple of officers stayed behind in her apartment, but the rest of the protection squad went with her. When she wanted to go home, the squad moved into position and checked everything out before they let her come back."

"She came home at around halfeight in the evening," Stone said. "So Tom had plenty of time to get up on the roof and plant the bomb and get out. But how did he know when she'd be coming home?"

"He didn't have to know the exact time. She always worked late."

"Are you sure?"

"I tracked down one of the guys who'd been part of the protection squad and had a little chat with him. He said that the assignment was a nightmare because Dr. Barrie kept crazy hours. Where are you going?"

"I'm following a train of thought. Wait there. It won't take long."

Tom Waverly had left a message at his sniper's position. He'd also spent some time on the roof of Eileen Barrie's house, so he might well have left a message there, too. Stone unlocked the padlock and stripped away police tape, switched on the borrowed flashlight, and stepped into the dark hallway. The ceiling had come down and there was a strong smell of smoke and burnt paint and charred wood. He picked his way through fallen plaster and puddles of water to the staircase and climbed all the way to the top, where the door to the building's flat roof hung on a single hinge.

The cluster of brick chimneys had been collapsed by the explosion and the roof had caved in around them, exposing blackened beams. Stone skirted the hole, played the beam of the flashlight over the waisthigh brickwork at the front of the roof but found nothing of interest, then clambered onto the roof of the neighbouring brownstone, the one that Tom Waverly had broken into.

Stone paced the perimeter of the roof, shoes crunching on gravel, and flicked the beam of the flashlight this way and that. There were fresh cigarette butts and a crumpled softdrink can by the dividing wall, probably dropped by the police sharpshooters. There was a junked air conditioner. And there was an aluminium lawn chair set beside the balustrade at the front of the roof.

Although there could be a perfectly ordinary reason why there was a chair up here-perhaps someone liked to sit on the roof on fine summer days, taking in the view across the river to New Jersey and catching some rays-Stone got a little chill when he saw it. He walked over to the balustrade and looked down at the road, the chain of streetlights, the sawhorses blocking off the sidewalk in front of the brownstone, the taxi parked in front. In the sodium lamplight its roof was the colour of an old bruise. He sat in the chair and looked at the trees in the long narrow park, the streetlights of the Hudson Parkway, the New Jersey shore twinkling across the river . . . and remembered Tom Waverly sitting in a similar chair on his lawn at one or another of his barbecues, a drunkenly benevolent potentate watching his daughter search on her hands and knees for the coins he'd hidden in the grass. The chair set in what Tom claimed to be his favourite spot on Earth, where he liked to drink beer while watching the sun go down beyond the little lake; the search for coins scattered around it a little game that he and Linda loved to play.

A treasure hunt.

Stone trailed his fingers in the gravel on either side of the chair, then dug deeper, his fingertips scraping tar paper beneath the gravel, finding nothing. But Tom had hidden coins under his chair too. Stone set the chair to one side and started to sift through the patch of gravel. Almost immediately, he found a scrap of thin card: the cover torn off a book of matches. It must have been placed there recently, because it was unwrinkled by time and weather. Chills chased up and down Stone's spine when he held it in the beam of the flashlight and saw what was written there.