I could reach no possibilities in which Johnny Rivers—wise guy, bootlegger, crook with his eye on the big time—still clung to life. In every crime scene every one of me was looking at, he lay face-down on the floor with two bullets in his back. It was a pity. Not because Chicago was particularly the worse off for one more dead mobster, but because murders are murders, and solving Johnny’s would have been a whole lot easier if he’d lived long enough to tell me who had pulled the trigger. Maybe, in another universe, another me had shown up sooner and had gotten something out of him.

That me was a lucky woman.

It was one of those drab Chicago winters, the kind where every sunrise brings fresh bodies on the sidewalks. At least this one was indoors. The shooting had taken place in the basement of a disused housing project just off of West 21st Street, which was, we had just discovered, the center of one of the Rivers gang’s bigger bootlegging operations.

The details of the crime scene didn’t vary much between universes. Metal slatted stairs led up to the street outside, and a jumble of distilling equipment—drums, pipes, a big tin bathtub—shone grimily in the light of a single, swaying light bulb. In one universe the tub was on its side, leaking moonshine into the floorboards. The Johnny in that possibility had flung an arm out as he fell, I guessed. It didn’t change much: all of him had fallen in pretty much the same direction, cut down by a shooter on the stairs. I felt my heisen implant work behind my forehead.

I tucked my hair into my collar and knelt to examine the body. Two entry wounds: one to the right of the spine and another just below the shoulder. I traced my finger around the edge of one of them and let the heisen throw up possibilities.

—an acrid cough of gunpowder—

—a shell casing tinkles as it bounces into a dark corner—

—rubber soles slip on the stairs—

—a small grey pistol leaps from clumsy, sweaty fingers—

There!

Other universes closed around me. I clung to the possibility thread that I had plucked out from the throng, visualizing it as a literal rope clutched in my fist. I felt like I was falling—the walls lurched briefly into the ceiling—then all at once I stopped, and I was standing in the basement—just one of them—listening to the faint wash of traffic on the street outside.

In this universe, the murderer had dropped the gun.

I found it in the shadows underneath the stairs, an evil glint of metal. It was a snub-nosed pocket pistol—kids’ stuff, really, compared to what a lot of hoods were carrying, but I didn’t doubt that it had spat the lead that was now in Johnny’s back. It must have dropped between two slats as the shooter fled up the stairs. I squatted down to pick it up, the tail of my trench coat brushing my heels. The gun’s potential buzzed beneath my fingers.

—a flashlight cuts the darkness, swinging, frantic—

—fingers search and scrabble, desperate to close around the handle of the pistol, to retrieve the evidence, dispose of it—

I took my hand away. I stood up, pinned the gun beneath the toe of my boot, and skidded it further underneath the stairs. That possibility was worth leaving open.

“Moore!” It was the first time I had used my voice in a half hour. He took a second to reply.

“Yeah?”

“All done.”

Light spilled in from the street outside and Detective Moore descended, feeling his way down the handrail. He had his eyes screwed shut.

“You worked your magic?” he said. “Can I look now?”

“Open your eyes, wise guy.” As if it made any difference now whether he looked or not. It did keep the possibility lines clearer on my end if he stayed out of the way while I searched the scene, though, and he might have closed a lot of universes to me had he come down first. He looked around and whistled.

“Nice little set-up he had here. You know half the joints in this neighborhood carry his booze and no one else’s? Not that he gave them much choice in the matter.”

It was West Chicago’s worst-kept secret that Johnny Rivers’s gang of toughs had bribed, bullied, and beaten the owners of half the local speakeasies into supplying their patrons exclusively with liquor from his distilleries. I’d have been dumb to think that this basement was the biggest one; Rivers’s operation spanned a lot of streets and ruffled a lot of feathers. The list of people in Chicago who might want him dead would be as long as my arm.

“Two bullet wounds, probably from a small firearm,” I said. “Our shooter comes in, gets Johnny clean in the back while he’s checking the equipment or whatever, and makes his escape. Any wild hunches on who did it?”

Moore took his hat from his head and went over to the body. The stink of spirits crawled into my throat.

“I know the Montagnios are sore with Rivers,” he said. “He makes his stuff a lot cheaper than they can. Sells it cheap, too. There was an attempted shooting over on West 14th a couple days ago—one of the boys working the case reckons it was the Montagnios butting heads with Rivers’s lot.”

I chewed my fingernails. Using the heisen for any length of time left me dying for a smoke, but there was no way I was going to light up in here, not with everything soaked in moonshine. “What about Big Dakota? He still doing the dirty work for the Montagnios?”

“Yeah…”

—a slight frisson of something in my head, like my brain had passed over a set of points on a railroad and clunked onto a different track—

“…but it wasn’t him,” Moore continued. “One of our boys over on the east side took him in last night—raided a brothel on 18th and caught him with his pants down. Literally.”

I pinched the bridge of my nose. “And Rivers was last seen when? And by whom?”

“By his wife, around seven thirty.”

I folded my arms across my chest and looked up at the light bulb. Why did I never get the universes where things were cut and dry? I fished in my pocket for my cigarette case.

“I guess I’d better speak to his wife, then.”

*   *   *

I interviewed the newly-widowed Mrs. Rivers in the station that afternoon. It was grey and frigid still, and on her way inside the building a cab kicked up a puddle by the sidewalk and splashed her heels with slush. I helped her dry off when we got up to the office. I offered her a glass of water, which she declined, and told her to take as long as she needed, which she did. I let her sit in my chair and watched her eyes follow the plainclothes detectives around the room. The office rattled to the sound of typewriters.

“I’m real sorry,” she said, dabbing at her eyes. “I think I’m still—Johnny, you know. I still can’t believe it.”

She was a delicate little thing; the kind of broad these gangsters tended to go for, I guess. Her first name was ‘Kitty’, although she looked more like a china doll: big timid eyes, bow lips, a nose with the slightest pig-snout lift. Her cotton candy hair looked like mine had when I was a little girl.

“Mrs. Rivers,” I said, pushing that unwanted association aside. “Could you tell me—?”

“Kitty, please,” she said earnestly, and pulled yet another handkerchief out of a sleeve apparently stuffed with them.

My implant twitched. “I don’t know if that’s really—”

—petite shoulders slump a little further; a white hand comes up to pull the fur scarf over the tip of the chin—

“Kitty, then,” I said, jumping with both feet into the universe that kept us on good terms. Her head lifted slightly. Her face was buried under a snowdrift of makeup. “Could you tell me about the last time you saw your husband? I know it will be tough to talk about. Remember, though—we want to help you. We want to find whoever did this.”

She nodded, once, and drew a Marlboro from the pack I offered her. It took her a couple tries to get it to her lips.

“Yesterday,” she said, once she had taken a drag, “Johnny came home about six.”

I nodded encouragingly. Watching her suck on the cigarette was making me crave a smoke myself, but I forced my attention onto the possibilities the heisen was throwing at me. The more Kitty’s story varied between universes, the more likely it was that she was making it up as she went along; the more similar, the more likely she was telling me the truth—or that the story had been carefully rehearsed. Shadows of those possibilities stretched out on either side of us, rows of doppelgangers interviewing and being interviewed, as though Kitty and I were caught between two mirrors.

“…and he went out again at around seven thirty,” Kitty said. “He—”

“—said he needed to go back to his office—

“—wouldn’t tell me where he was going. Said it was nothing to do with me—

“—didn’t say a word when I asked him where he was off to—

“—and he left. By eight o’clock I was getting worried. By nine I was imagining all these terrible things that could’ve happened to him. By eleven … I got a cab over to his office on West 21st. Heard a gun go off as I was getting out.”

“Did you see anything?”

She stubbed her cigarette out in the ashtray on the desk and twisted her handkerchief around her finger.

“A man,” three Kittys said in unison. “Running down the street. I didn’t see his face. He might—I think he was wearing a hat.” She glanced up at me. “After that I—I went into Johnny’s office and I saw—I found him—lying—”

She pressed the handkerchief to her mouth. Her shoulders shook.

“Take as long as you need.”

“I ran all the way to a callbox on 20th,” she said, “and called the cops. I didn’t—I couldn’t believe it. Him just lying there, I mean. He never meant no harm, Detective, I swear…”

I poured her a glass of water. She was just a kid, when it came down to it—eighteen, nineteen; easily young enough to be my daughter. Too young to be married to some dead gangster.

“Here.” I held the glass out to her.

“Thanks.”

—the water falls into her lap: for a second, the young woman drops her guard—

I jerked my hand back as Kitty’s fingers closed around the top of the glass. The rim slipped underneath her thumb and the whole thing dropped into her lap.

“Ah, darn it, Kitty, I’m sorry … here.” I drew my own handkerchief from my pocket and knelt to dab at her dress. I felt her slim legs tremble through the fabric.

“It was my fault,” she said, and looked at me with wet, red eyes, like a child. The glass rolled along the floor and stopped at my knee.

“Kitty,” I said seriously. The handkerchief still rested on her thigh. “Do you have any idea who might have wanted Johnny dead?”

She sucked her cushioned bottom lip. “I—” She dropped her eyes to her lap. “Two men came to see him a while back. Months ago. I don’t know what they wanted—Johnny made me leave the room as soon as he saw them. But there was one fella the size of a truck—fair-haired, scar on his neck—”

Big Dakota. Moore reckoned our boys on the east side had already ruled him out.

“—and another guy, dark, a little heavy; I think the other fella called him ‘Quine.’”

That would be Vincent Quine, I guessed—another Montagnio tough, and a first-rate slimeball. Kitty twisted her handkerchief around like she was wringing out a dishcloth. “Is that”—she stopped and got her voice under control—“is that any help? Do you have anything … any clues to go on?”

I stood up and put my handkerchief back in my pocket. The sun was already low and squinting through the window blinds. “All we have to go on,” I began, and hesitated. The pistol I had left beneath the stairs hovered in my mind. “All we have to go on is what you just told me and a couple bullets we found at the scene.” I turned to my desk and started leafing through some papers. “It might be that we check the distillery again once we know what we’re looking for, but … Excuse me.”

Moore was staring at me from the doorway, tapping an envelope against his lips and looking thoughtful.

“Not like you,” he said, when I approached. “Falling for the bereaved widow act.”

I turned my head. Kitty was staring into space and picking at her handkerchief. “She’s just a kid,” I said. “Did you want something?”

“For you.” He held out the envelope and I saw the familiar handwriting.

Detective O’Harren, c/o Chicago Police Department, etc. etc.

“Still not giving out the home address, huh?”

I took the letter without looking at him.

“Mrs. Rivers needs escorting home,” I said. “I think you just volunteered. Oh, and while you’re out—see what the word is on the street about our old pal Vincent Quine.”

*   *   *

Snow scrunched beneath my boots as I made my way home that night. It was cold, and quiet: only the occasional hum of a car or smatter of distant voices on the wind disturbed the silence. I turned at the corner of Trumbull Avenue and slid my key into the door of Number 17.

Mrs. Long was already asleep. I knocked the worst of the snow from the bottoms of my boots and made my way upstairs, taking care not to let the door to my room slam shut. I locked it behind me. I probably didn’t need to—even when awake, Mrs. Long knew not to disturb me—but the possibilities that it excluded made things easier.

I hung my wet coat on the door and put the letter from Rick with the others, unopened. The tired old rubber band I was using to hold them all together snapped. I swore, stuffed them under the bed, and lay down, my head full of the usual letter-questions. How was Sarah? Did she miss me? Did Rick? He must; enough to keep writing every few months with no reply, at any rate. Unless he did it out of pity. Was he seeing anyone? I turned onto my side and stared at the wall.

I wondered, sometimes, if Rick had already been seeing someone else before the end—if maybe that was why he’d left—but I knew that I was just looking for an excuse to blame him instead of myself. There hadn’t been anyone else. Not in the universe I was living in, at least, although there must have been others in which other Ricks had been unfaithful to other mes. Not that I blamed them. I was the one who had pushed Rick away. And Sarah. I had lost them both, one day at a time, starting from the day I woke up on the operating table with the implant in my head and didn’t know which ‘me’ was me.

It helps if your life’s already in pieces when you get the heisen implant. Less to adapt to, that way.

I thumped the pillow. Feeling sorry for myself wasn’t solving Johnny’s murder. Wasn’t that why I had gotten the heisen in the first place? To be a better cop? It was in my head forever now, so I might as well make use of it. I closed my eyes.

We didn’t have the manpower to have someone watch the basement on West 23rd every hour of the day and night—if I wanted to see if anyone came back for the gun, I’d have to do it myself. But I couldn’t afford to spend all night on stake-out, not when there was so much work to do during the day. I’d be exhausted.

Unless it wasn’t me that went.

I imagined closing myself inside a box. It was something that they’d taught us during training, a visualization exercise: imagine that you’re Schrödinger’s cat. No one knows if you’re alive or dead. Except, in the quantum language of the heisen, it’s more than that: you’re both alive and dead, a million quantum cats existing in both states at the same time.

Alive and dead.

West 23rd Street and Trumbull Avenue.

Another me climbed out of bed and slipped into her coat.

*   *   *

The following afternoon, I went to speak to Vincent Quine. I’d gotten a full eight hours’ sleep the night before: nothing had happened over on West 23rd Street that was worth seeing, so I left that possibility thread to another me and decided, with a flick of the heisen, that I had been in my bed all along. I tracked down potential Quines, ignoring the more isolated and unstable possibilities that would send my investigation hurtling down an unpredictable path, such as finding him dead in the road on Ellen Street having been struck by a cab that skidded on a patch of ice.

In most universes I found him in a speakeasy joint above a bookstore on Evergreen Avenue. I’d been there before: it served awful bathtub cocktails, mostly to gangsters, and was little more than an attic space with a bar along one side. It had never really been worth raiding. I chose a universe in which I remembered the correct pattern of knocks to gain admittance and slipped through the door before the bartender could shut it. All conversation in the place went dead as I stepped inside.

“Afternoon, fellas.” They’d squeezed a pool table into the far corner since I’d last visited. Quine and a couple cronies stood around it, cues resting on their shoulders. There must have been ten, fifteen other hoods in there—half of them drinking, most of them smoking, all of them wearing suits. I looked each of them in the eye, one by one.

—a hand plunges into a coat pocket, but other hands are faster—

—a cacophony of bangs as hot lead screams across the room—

I spread my palms to show I was unarmed and looked towards the bar. “What’s a girl got to do to get a drink around here?”

Smoke drifted lazily towards the ceiling. For an awful moment I thought I was going to end up splattered across the wall, then someone laughed and the tension broke. Heads turned away; conversations resumed. The bartender hurried over with a waxen smile.

“Good to see you, Detective. Here—on the house.”

Awful-tasting cocktail in hand, I made a beeline for the pool table. Quine was leaning halfway across it, squinting down his cue. He was a big guy. Most of it was muscle, although when he undid his jacket I could see a hairy fold of beer gut through the gaps between his shirt buttons. His slick black hair was lovingly oiled. Chicago legend had it that he had a messy scar on his leg from a badly-healed bullet wound: he’d plugged it with a finger during a gunfight and had refused to go to a hospital.

“Came down to the nine, I see.”

He squinted up at me. In all but one of the universes spread out in front of me he made the shot and won the game—I thought victory might make him more amenable, so I chose one of those. The balls clacked together and the nine-ball shot into the pocket, the cue ball bouncing softly off the cushion and carrying on around the table. With the heisen’s help I pinned it first try beneath my index finger as it came towards me.

“Fancy a game?”

Neither of us spoke while I set up the balls inside the diamond. It was obvious that I wasn’t on a social call. I took off my coat and flicked my hair out of my collar, wanting to see Quine sweat while he tried to work out how much I knew. He handed me a pool cue, chalked end first.

“So, Detective,” he said. “Are my tax dollars paying for you to come play pool nowadays, or are you here on business?”

I took the cue and dusted the little cube of chalk around the tip. “Johnny Rivers is dead.”

He nodded gravely. “So I heard. God rest his soul.”

I watched him cross himself and tried to gauge his reaction. I had expected him to feign ignorance. “You’ve certainly got your ear to the ground,” I said. “He’s not been cold forty-eight hours.”

“News travels fast in Chicago. You break.” He placed the cue ball behind the line and stepped aside with a gentlemanly bow. One of his cronies lifted up the rack. “Besides,” he said, as I chose a possibility that gave me a good break without potting any balls, “he was a friend of mine.”

I tucked my hair behind my ear. “Don’t take me for a fool, Vince. Everyone and her mother knows he was the biggest rival you lot had in this part of town.”

“Well, Detective, you know what they say. Keep your friends close, and your enemies”—he pocketed the one—“closer.” He shot again and bounced the two into a cluster of high balls, leaving the cue ball penned in near the corner pocket. “But that’s it, isn’t it? You want to pin Johnny’s murder on me. Jeez. You know what—I ain’t even surprised, what with the way your boys have been on my back lately. Need a suspect for a lineup? Get Vincent Quine. Someone done a robbery? Must be Vincent Quine. Seems like a cat can’t have kittens in this town without me getting blamed for it.”

“Oh yeah,” I said, sliding the cue into the groove between my thumb and forefinger. “Poor, innocent you.”

By my count, Quine had dodged three murder charges already that year, all of them dropped due to lack of evidence. The prostitute who had agreed to testify against him for the Dickson murder had been lured to her death by Montagnio goons pretending to be federal agents. Her body turned up in Lake Michigan a month after she disappeared. No way to prove anything, of course, but the story spread fast enough to make any other potential witnesses think twice about doing society a favor. I opened up a universe in which I made the cue ball hop over the eight and roll into the two, just to put me back in the game. Suddenly I didn’t want to lose.

“What you got on me this time, then?” Quine took a gulp of his drink while he considered his next shot. “Prints? Witnesses? A little handwritten note saying ‘Detectives, you ain’t picked on Vinnie Quine enough—he did it!’?”

I jumped universes as his cue came forwards, grabbing hold of a possibility thread in which he slipped and struck the cueball on one side. It spun off slowly at an angle and collided with the seven.

“Whoops.” I knew that I was pushing it, using the heisen to manipulate the game to this extent, but I wanted that smirk wiped off his face. It was only when two balls smacked together with a gunshot crack that I remembered the trap that I had come to set.

“You know I wouldn’t be wasting time chewing fat if we had solid dirt on you,” I said. I watched him as I sipped my cocktail. Did he look relieved? Was he thinking of a stubby pistol, dropped in a scramble up the stairs? I made a show of estimating the angle needed to bounce the cue ball off the cushion in order to connect with the two. “But you had means, motive, and opportunity, so—”

“I also have an alibi.” He ran the back of a finger over his lips as he surveyed the table. “I was eating at Giordano’s, over on the other side of town. All night. Ask anybody.”

“Giordano’s?” I said, as he took his shot. “Come on, you’ve got to do better than that. The Montagnios as good as own that place.”

The two knocked the six into a pocket.

“Hey—if I was there, I was there. What do you want me to do, puke up some pasta to prove it?”

He grinned and took another shot, once again ensuring that I had to make mine from an unfavorable position. I chalked my cue. With a bit of possibility manipulation I managed to ping the nine close to a pocket a few times without fouling, although I was careful not to be too lucky. (There were a couple one-in-a-million shots that I knew would tick Quine off, but I had my temper enough under control not to risk it.) We played in silence until there were only two balls on the table. It was Quine’s shot when my implant buzzed.

—a name, dropped into the silence—

“Mrs. Rivers,” I said, seizing the possibility before I really knew what I was saying. Quine twitched and caught the cue ball on its upper hemisphere. It floated off at a wide angle. “I don’t suppose you thought about her? She’s distraught.”

He stared at me for a moment, his blue eyes searching my face. Ice clinked into a glass somewhere behind me. Quine snorted, then coughed: for a moment, as his shoulders bucked, I thought that he was choking, then I realized he was laughing.

“Mrs. Rivers? You mean Kitty?” He shook his head and pulled a handkerchief from his inside pocket. “Distraught? If I had to put fifty dollars on it I’d say she was the one that did it. She—she didn’t tell you that she—?” He continued his exaggerated display of mirth, slapping the edge of the pool table for good measure. I stood and scowled at him.

“If you’ve got something to tell me, tell me.”

He wiped away imaginary tears. “Johnny Rivers,” he said, “didn’t want Mrs. Rivers to be Mrs. Rivers no more. You know how long they’ve been married? Eight months. That’s it. But then a month or two ago Johnny meets this other broad—beautiful young thing; an actress—and he falls hard for her, even harder than he did for Kitty. I know, I know, men are pigs.”

He laughed again as I stoked my implant into life. There were very few universes in which this story went any differently, which suggested that it was likely to be true. I sipped my drink as he continued.

“So the way I heard it was, Johnny promises this broad the moon; says he’ll marry her right away. Now, he knows that Kitty would fight tooth and nail for whatever she could get if he wants to divorce her, so—and this is the stroke of genius—he calls up Judge Binford—you know him?”

I did: he was a judge so crooked you could use him to uncork wine.

“He calls up Binford and asks if he can get the whole thing annulled. Get him to say that they were never legally married—never consummated, something like that—and that he don’t owe her a cent!”

He lapsed into laughter again, mirrored obediently by his cronies. My mind worked double-time. “And did he? Did he get the marriage annulled?”

Quine folded his handkerchief fastidiously into a square and tucked it back into his pocket. “I heard he was supposed to be sorting things out with Binford tomorrow afternoon.” He made a grimace. “I guess the appointment’s off.” He nodded at the pool table. “It’s your shot, Detective.”

My heisen let me pocket both the seven and the nine-ball in one dazzling, unlikely trick shot.

*   *   *

I lay on my bed in Trumbull Avenue and stood in an alcove on West 23rd Street at the same time, sheltering from the snow. When I closed my eyes I could still see the smirk on Vincent Quine’s face. I hadn’t bothered to check his alibi—the guys at Giordano’s would swear that he’d eaten there every night since he was in diapers if they thought that was what he wanted. Every piece of evidence he produced to the contrary only made me more certain he was guilty. Even so, I had to check out what he’d told me about Kitty Rivers. I’d asked Moore to find out her address and invite her in to talk to me, one-on-one. Hopefully I’d gained her trust during our last encounter. In the meantime, both she and Quine believed that the murder weapon had not been discovered. Whichever one of them had dropped the gun knew that it was still there somewhere, out of sight, potentially ready to betray them if it were found. It would be the work of an evening to come back and remove it.

Wind rushed through my bones. I could almost hear Rick’s voice in my head as I huddled closer to the wall. “Why bother?” he had asked me once. “Even if you bring this guy down now there’s gonna be about a million other universes where he gets away scot free, right?”

I remembered a summer evening, standing on the balcony with Sarah in my arms, trying to light a cigarette one-handed.

“Because if I don’t bother,” I said, “he gets away in a million and one.”

That was the Alano murder case, one of the first I’d worked after having the heisen implant. They’d tried to warn me what it would be like—I’d taken all the classes, scratched my head over the science, passed the temperament tests in the federal facility in Minnesota, learned all about goddamn Schrödinger’s goddamn cat—but nothing had prepared me for the reality of it all. Well, realities.

My baby girl, my joy, my Sarah—for those first few weeks I couldn’t look at her. Not without seeing a spectrum of all that she could or might or would never be, every glorious and terrifying possibility fanning out around her. I brushed against universes in which I slipped and dropped her off the balcony, or accidentally smothered her beneath a blanket. They were outside chances, but they followed me like specters. Rick was no better. He was suddenly a million different people—Rick if I said this, Rick if I said that; Rick who could fall out or back in love with me a thousand different ways—and I withdrew, not knowing which of him I loved.

I adjusted, over the next six years, but the damage had been done. I knew that Rick was ready to walk out and take Sarah with him. I knew that I deserved it, too. I’d become a ghost in my own family. I should have done something, but I couldn’t—somehow I couldn’t turn my back on all those possibilities. They plagued me, every day, showing me what our lives could be—what I could be—but I didn’t have the guts to go for one and shut out all the others. Then, one day, I came home to find all my immediate possibilities the same. The note on the kitchen table read:

We’ve gone—will write. R.

That’s one thing they don’t tell you about Schrödinger’s cat: you leave the lid on the box too long and the damn thing starves regardless. No quantum possibilities required.

*   *   *

“She’s over there,” Detective Moore told me when I got in the next morning. Kitty Rivers was drooping in a chair over by my desk. “She’s in a pretty bad way.” He handed me a mug of coffee and peered into my face. I knew that there were shadows underneath my eyes.

“Are you okay?” He laid a hand hesitantly on my shoulder. “I can talk to her if you want to rest.”

I looked at him—broad nose, big white teeth, face all concern—and smiled. I’d seen the possibilities these interactions bred—

—strong, soft arms around my back, hot breath against my cheek—

—but I always steered well clear of them. I shrugged him off and drew my collar up around my neck. Other mes knew whether that road led to any kind of happiness.

“I’ll be fine,” I said. “Anything else I need to know about?”

He turned and picked up some photographs from his desk. “Frank Campagna. Henchman for Johnny Rivers—muscle, I think, but in a position of trust. Shot dead yesterday getting out the barber’s chair. Colbourne sent these across this morning. Says the Montagnios have made no secret of their involvement.”

I riffled through the photographs. There was a lot of blood and broken glass. “So we know that the Montagnios are definitely out for Rivers and his gang,” I said, handing them back. “But did they send Quine to take out the boss first, make an example, or did his soon-to-be-ex-wife beat them to it?”

Moore gave an exaggerated shrug.

Kitty Rivers was staring at the wall when I went over to her. I put a hand on her shoulder from behind and she jerked as if electrocuted. Her beauty was haphazard today: her fashionable hat was pinned lopsidedly on her head, and her hair had deteriorated into a greasy mass of unwashed blonde. Her face was clean of makeup. Without it I could see, faintly but unmistakably, a yellow island of bruised flesh around her left eye. I pulled out my chair.

“Would you like a cigarette?”

She burst into tears.

I calmed her down eventually, patting her on the back and filling her lungs with an endless chain of Marlboros. She brought each one shakily to her lips, trying to control her sobs, and sucked the tiniest bit of smoke from it before exhaling and letting her hand sink back into her lap.

“Have you been to a doctor about your face?” I said eventually. Kitty pulled away as I tried to touch the bruise.

“No.”

“Looks bad.”

She stared at the potted plant in the far corner. “Johnny did it,” she said. “I saw him on West 19th a few days ago, the first time since he … moved out.” When I made no reply she flicked her doe eyes up to mine. “You know about that?”

I nodded slowly. She sniffed and looked back down.

“Chucked me for some other broad. A singer, or something. Anyway, I—this was the first time I saw him since he walked out, like I said. So I gave him a piece of my mind: told him I thought he was a rotten, dirty cheat and I hoped he died in a gutter. I said I’d hire the best divorce lawyers in Chicago and that I’d get what was mine if they had to turn him upside down and shake it loose. And he—and he—”

She covered her face and cried into her hands, her pretty little shoulders jerking with each sob. I patted her some more and went to get some water. I avoided universes in which it spilt this time.

“Thanks,” she said, once she’d had a sip. She put the glass back on the desk. “So I told him—what I just told you—and he—he did this.” She gestured to her cheek. “Told me I was a dumb bitch and that I wouldn’t get a cent. Some old pal of his was going to get our marriage undone, say that we never—that I was never Mrs. Rivers. And he told me that if I came near him again he’d…” She bit her bottom lip and tried to stem the tears.

“It’s okay,” I said, as gently as I could manage. I didn’t know whether I should touch her again. In the end I got up, went around to her side of the desk and knelt beside her chair, looking up into her eyes. She rubbed away her tears and looked fiercely at me.

“Kitty,” I said. “There’s one more thing I need to ask you; it’s about the night Johnny was killed. Last time we talked you told me that you went to the distillery because Johnny hadn’t come home and you were worried about him. That’s not true, is it? He hadn’t lived with you for weeks. What really happened that night?”

She looked over at the window. “Her,” she said eventually. “I wanted to see who she was—who he left me for. I hired a PI to shadow him. He found out where Johnny was living and told me that he went out most nights with a broad, so I decided I’d follow him. On the night he—the night he died—I waited outside his apartment. I figured she’d be there with him, but he came out alone. Got into his car. I hailed a cab and followed him. Ended up on 23rd, near his”—she glanced at me—“office. I waited in the cab, wanting to see if he came out with her—next thing I knew, I heard a gun go off, and I saw a man running away. So I got out of the cab, and—and…”

I put a handkerchief in her hand: she pressed it gently to her nose and blew. I touched her knee. It had been a long time since I had comforted anyone.

“It’s okay,” I said, aiming for tenderness. “It’s okay. Why didn’t you tell me this before?”

Kitty’s face was scrunched and wet. I fired up the heisen to try and tell if she was faking it, but what she did next was the same in every universe that I could see. “Because I—because I didn’t want you to think—” She threw her arms around me, her chin digging into the inside of my shoulder. “Please don’t think I killed him, oh please, I didn’t kill him, I wouldn’t kill him…”

I patted her small, soft back and let her sob into my sleeve.

*   *   *

Later that afternoon, over on the East side of Chicago, I watched the sun sink behind a square apartment block. I stood across the street, outside what had been the back yard of a brewery before the prohibition, my implant churning. The stack of letters bulged inside my pocket.

Rick had not kept his new address from me, as I had mine from him when I had moved out of our shared apartment. I guess he thought that one day I might want to come and see Sarah. Or, at least, that I would want to keep that possibility alive. A boy walked down the sidewalk carrying a violin case. The apartment block was blurred to me, like I had something in my eye; what was really happening, of course, was that the heisen was showing me all the thousands of possibility threads for this place laid on top of one another: lights in windows on or off in different combinations, graffiti gone or changed or further to one side. Hundreds of potential snowfalls fizzing in the air. In one or two universes, the boy with the violin case was a girl. Spectral figures moved behind the windows.

I tried to work out why I was there. I’d kept the lid on my curiosity for twelve years. I’d left forty-eight letters unopened. I’d always had the possibilities to fall back on—

—maybe Sarah doesn’t hate me—

—maybe she wants to be a cop—

—maybe she wants to get the hell out of this messed-up city—

—but now, something was different. I counted the windows, up and along, trying to work out which was apartment 13B. A light came on just as I found it. The faint outline of a blonde head bobbed past the window.

Longing kicked me in the gut.

The girl—young woman, I suppose—drifted through the room, followed by a thousand other versions of herself. Some had short hair, some had long; some were beautiful, some were not; some had eyes that were grey and heavy, some wore smiles that were full of hope. I knew that she was—that they were—Sarah. My baby girl.

In one universe, faint as the very outside of a shadow, another woman appeared behind Sarah and placed an arm around her shoulders. She was in her early forties: strong chin, dirty blonde hair, hooded eyes. As I watched, I swear she looked right at me. I drank in the sight of her before the curtains closed.

I blinked. It had grown almost fully dark, and my breath was starting to come in clouds. The street lamps were orange. I took the bundle of letters from my pocket and extracted the earliest: coffee-stained, slightly yellowed, grimy from the old rubber band that had held it to the others until a day or two ago. As snowflakes settled wetly on the paper my memory threw up a conversation I had almost forgotten, one that I’d had with Sarah near the end:

“So, the cat is inside the box, okay, and there’s a flask of poison in there, too, which can break open at any time. The cat might die and it might not. Now, we don’t know if it’s alive or dead in there until we open the box to check. Okay?”

I remember thinking that it was a dumb thing to do, trying to explain quantum physics to a six-year-old, but Sarah was a smart kid. She just looked up at me with her big, doleful eyes and listened.

“But it’s not just that we ‘don’t know’, it’s that there are really millions of potential cats, alive and dead, and opening the box collapses them all down into just one, which is alive or dead. That’s what mommy’s head-chip does.”

She considered this, eyes on her lap, for almost a minute, then looked up and said, “The cat must know.”

The Chicago evening closed around me. I looked up at the curtained window and then down at the letter in my hand. I plunged my thumb into the envelope.

*   *   *

I dozed standing up on West 23rd Street. As was usual by now, I was both there and in my bed in Trumbull Avenue at the same time, my implant straining to keep both possibilities open. It had gotten too cold even to snow: the sidewalks were locked in frost and my breath was as opaque as cigarette smoke. I huddled into the wall/pillow and closed my eyes.

—Kitty Rivers—

—Vincent Quine—

—a blunt-nosed pocket pistol underneath a staircase—

My thoughts ran through the same tired grooves. Who shot Johnny Rivers? Was his death simply a part of the grim business of Chicago—a hit put out by a rival gang and executed by a thug who’d killed before and gotten away with it—or was it a crime of the heart, an act of revenge by the woman he had pushed too far?

I think I started dreaming. Vincent Quine oozed past me, stretching and distorting like he was in a house of mirrors. Kitty Rivers showed me her bruised cheek and started crying, turning into Sarah when I tried to comfort her. For a moment I saw all of Chicago as a mist of endless possibilities. Bullets flew from guns, hit, missed, ricocheted; bodies fell, crumpled, folded, flew, sank, rolled, were discovered or kept secret; revenge was or wasn’t or was almost taken. A million stories hovered in the smoke.

I woke to the sound of a door slamming shut.

It took me a moment to work out which reality I was in. West 23rd Street was chill and bleak and someone had just got out of a car. It was too dark to see them clearly. They opened the trapdoor to the basement and disappeared inside.

I followed, reaching into my pocket. My gun was freezing to the touch. I trod stealthily over to the trapdoor and crouched beside it. The light had been switched on inside, but at this angle I could see almost nothing of the room below. I stood up and stepped over to the stairs.

Apart from Johnny’s body having been cleared away, the crime scene was exactly as I had left it. Distillery equipment glinted dully in the half-light. When I reached the bottom of the steps I drew my gun from my coat and stepped forwards, squinting furiously as my eyes adjusted. I heard a scuff behind me and spun around.

“Chicago Police,” I said to the shadow underneath the stairs. “Step out slowly, hands on your head.”

The figure moved into the light.

My heisen roared. It was impossible. What I was looking at was impossible. I felt my gun drift downwards as my arms lost strength.

They stood there, overlapping, like two different movies projected onto the same screen; a fault line between two universes. A perfect quantum tightrope. I was looking at the cat inside the box, alive and dead at the same time, and I had seconds left to choose which possibility remained when the lid came off. I couldn’t speak. For a moment, two versions of myself stood inside of each other, our hearts beating different rhythms.

The figure that had stepped out from the shadows was both Vincent Quine and Kitty Rivers.