Artwork by Nick Greenwood

"Daddy, did you ever live with Mommy?"

I fix my eyes on the road and ponder what brought on the question. Kayla's in first grade and noticing that many of her classmates have mothers and fathers that live together.

"No," I say. "We worked together, but never lived together."

"Mommy was a fireman?"

"No. She worked at the university. I was a teaching assistant back then."

"Oh," she says. "Did you ever live with Daniel's mommy?"

"Yes." Daniel's her older brother. I've already dropped him off at Beth's house after taking both my kid's trick or treating. Daniel's eleven; he announced as he left the car in his Superman costume that he thought he'd be too old to trick or treat next year. I hope he's wrong. On almost every other big holiday, my ex-wives' trips out of town conspire to keep me from spending time with both my kids at once. Luckily, it's always worked out that I can take both of them trick or treating.

"When did you stop living with Daniel's mommy?" Kayla asks, wadding up the edge of her Supergirl cape.

"A while ago," I say. Six years ago is the precise answer, and maybe the answer she's digging for.

"Before I was born?"

"Before you were born."

"Why didn't you ever live with Mommy?"

"We . . . weren't compatible."

She frowns, unsatisfied by the answer. Coward that I am, as much as I cherish each second I spend with my kids, I'm relieved as I pull into Sabrina's driveway. There's a flickering light from the living room, but her porch light is off. Sabrina's not really into Halloween. Handing out candy isn't part of her ritual for the night.

I hold Kayla's hand as we walk onto her porch. In her other hand she clutches her plastic pumpkin full of sugary swag.

Sabrina opens the door as we approach. She eyes the candy.

"I'll be the one dealing with her bouncing off the walls," she grumbles.

"Kayla can stay at my place if that would help you out," I offer. "I can get her to school and have my mom pick her up in the afternoon."

Kayla's face lights up. She likes the idea, but I know I've made a mistake. She's about to get her hopes crushed.

"I don't think it would be good for Kayla to have her schedule disrupted," Sabrina says, crossing her arms. The message is loud and clear. I get my court-mandated visitation, nothing more.

We talk for a few minutes about Kayla's school. Sabrina's answers are short, perfunctory. When they both go inside, I turn away feeling defeated. Sabrina doesn't switch on the porch light to make it easier for me to get back to my car.

I drive home aching. I love both my kids, they love me, and mostly love each other. But neither of their mothers, Beth or Sabrina, would pee on me if I were on fire. Of course, as a fire-fighting professional, I wouldn't recommend such action anyway.

For the millionth time, I think back over all the moments where I could have done things different. Saying "no" the time a professor fifteen years my senior attempted to seduce me would have been a good start. Telling Beth I was sorry and sounding like I meant it might have been another good move.

I squeeze the steering wheel hard, fighting back the flood of "what ifs." There are a thousand moments that leave me guessing what might have been. What if I'd stayed in school, instead of dropping out the first time to support Beth, or messing things up the second time by getting into an affair with a crazy woman?

Who knows? If I'd kept studying physics, maybe by now I'd have built that damned time-machine I always daydream about. Maybe run some tests to figure out if I could have made smarter choices.

I pull into my driveway. For a moment I study my eyes in the rearview mirror. The lines around them grow deeper each day. I try to remember a time when I could look into mirrors and see eyes not filled with doubt. I try to remember a time when I didn't find myself staring at the eyes of the man who haunts me, the man I might have been if I'd used my brain at pivotal junctures in my life instead of my groin.

I open the car door with a sigh. I cross my leaf-covered deck to the back door. Inside I flick on the lights and head for the fridge. Putting my phone on the kitchen island, I retrieve a beer, then head for the living room.

I freeze. There's a man standing in front of me. Everything about him is familiar. He could be my identical twin, if I had an identical twin. Only our haircuts are different; mine's trimmed close on the side and back with the top a little spiky. His long wavy hair is slicked back with what looks like Vaseline. Our facial structures . . . they're a perfect match. I stare into eyes precisely the same color as my own.

His face is so unsettling it takes me a second to realize he has a pistol aimed right at my chest.

"Welcome home, Gordon," he says. Even his voice is curiously familiar.

"Who the hell are you?" I ask.

"I'll be the one asking questions." He motions toward the couch with his non-gun hand. I notice he's wearing gloves, even though it's not cold outside. "Sit."

"What do you want?"

"I want you to sit," he says coolly. "I'm going to ask you questions. This doesn't need to be complicated."

"Questions?"

"Sit!"

I sit, never taking my eyes off his face.

He grabs a stool from the kitchen and takes a seat next to the bookcase. He picks up a picture of Daniel and Kayla from last Halloween. He's dressed as Iron Man. She's dolled up as a princess.

"You have children," he says flatly. "With Beth?"

"Beth is Daniel's mother."

"Daniel's the little boy?"

"Who are you? Why do you want to know?"

"I'm the man with the gun. Answer my questions or this will be a long night."

I cross my arms. "I'm not telling you anything that would endanger my kids."

"I assure you, I won't harm them. Who's the little girl?"

"Piss off," I say.

"Who. Is. The little girl?" He clicks a switch on the pistol and I see a bright laser glow atop the barrel. I don't need a mirror to know there's a red dot in the center of my forehead.

I'm tempted to lunge, to try to get the gun away. I'm definitely tempted to keep cussing at him, and not let him drag a single bit of information out of me. But . . . if he kills me, I'll never see my kids again, and he'll find out anything he wants to know about them by searching my house.

"Kayla," I say. "Her mother is Sabrina."

He gives a creepy grin. "What a player. Impregnating two women. Why didn't Beth have an abortion?"

"Why the hell do you want to know?" Suddenly, a theory forms. "Wait . . . is this . . . is this some kind of custody thing? Did Beth send you?" Beth constantly threatens to reopen the old custody battles, but sending a goon at gunpoint seems extreme, even for her. Sabrina . . . maybe.

A flicker of amusement comes into his eyes. "Why, yes. I suppose it is a custody thing. What's at stake here is the continued possession of your life."

Just then my phone rings.

He walks to the kitchen island where I sat the phone. His face grows pale as he looks at the screen.

"It's . . . your mother," he says softly. "How did she survive the fire?"

"The fire? You mean fifteen years ago? When our house burned down?"

"Yes," he says.

"I ran back inside when I realized she hadn't made it out," I say. "I kicked down her bedroom door. Her room was full of smoke. I couldn't rouse her, so I dragged her out. When the firemen came, they put her on oxygen and she recovered."

"I see," he says, sounding thoughtful. He turns to me, shifts the pistol into his left hand, and uses his teeth to remove his right glove. He's missing his pinky and the tip of his middle finger. White scar tissue crisscrosses his palm. "In my world, I grabbed the doorknob, not seeing that it was white hot. The pain caused me to retreat. My mother never made it out."

"Your world?" I say.

"You must know by now what's going on. How can you not grasp who I am? Though you seem not to have made use of your intellectual gifts, if you met Beth, you must have gone to college the fall following the fire. You must have studied parallel worlds."

"Yes," I say.

"But you didn't stay in school? Despite being a genius?"

"Beth got pregnant," I say. "My mother convinced me that the right thing to do would be to get married. I took a break from school, got a job as a dispatcher for the fire department. Made another attempt at school a few years later, but messed things up when I got romantically involved with a professor. I dropped out again, and didn't really get my life together until I became a fireman."

He looks bewildered. "You cheated on Beth?"

"Beth and I had . . . difficulties. If not for Daniel, I don't know that our marriage would have lasted as long as it did."

"Difficulties?" he says. "Beth and I were the perfect couple. There were no difficulties . . . at least until I convinced her to have the abortion. She had the absurd notion I was choosing my studies over her. She couldn't see that by staying in school I'd make the future better for both of us."

"Beth and I weren't even close to perfect." I shake my head at the old memories. "When I met Beth, I'd never been in a relationship before. I didn't have the maturity to grasp the irreconcilable differences between us. Neither did she."

"I refuse to believe that," he says. "I've reached 37 orthogonal universes so far. In one of them, I know that our love triumphed over all obstacles."

"Wow," I say. "You're nuts."

"Because I claim to have traveled between universes?"

"Because you obviously still love Beth. It sounds like you broke up with her before you ever lived with her. Trust me, there are a lot of things love is never going to triumph over."

"You're wrong," he says. "Orthogonal 3. There, Beth and I are happily married. Were happily married." His face turns grim. "On that world, we both perished in a plane crash while flying home from Geneva. I'd been awarded the Nobel Prize. It would have been paradise to live in that world, if not for a failed jet engine. Fortunately, I've an infinity of splinter worlds to search. In one of them, I've both my career and the woman I love, and we survive everything life throws at us."

I furrow my brow. "And . . . then what? You torture yourself by watching someone else live the life you could have had?"

"Then I . . . displace . . . my counterpart," he said, waving his pistol idly, "and live happily ever after."

"I can't believe there's a version of me anywhere so evil."

"This has nothing to do with good or evil. I'm using my natural talents to create the best possible life for myself, as any organism must. Other people are confined by their past choices. My genius allows me to escape such traps."

"Your plan is to find a happier version of yourself and murder him."

He smiles softly. "That's an unvarnished way of putting it, yes."

His eyes chill me. I now know what it's like to look into a mirror and see my eyes devoid of doubt. I don't like it.

"You disapprove," he says, amused. "Don't worry. I'm not going to displace you. I'm looking for a world where I have everything. You, it seems, are the version of me who has nothing. You've squandered both love and genius. What a waste." He gets down from the stool and pushes open his jacket to reveal a thick metal belt covered with wires. He grasps a knob. "I'll be moving on."

He lowers his gaze to adjust the knob, his gun-barrel dipping toward the floor.

A growl tears from my throat as I move with a speed I've never before possessed. He looks up as I fly from the couch. The pistol fires, but if it hits me I don't feel it. I tackle him and throw him to the floor. Somehow, we land on white tiles instead of my dingy beige carpet. I don't have time to wonder why. I'm on top of him, with one hand on his throat, the other on his gun hand. He claws my face with his free hand, his gloved fingers grabbing at my lips. I open wide and clamp down on his fingertips, biting until I taste blood. He arches his back as he screams. He loses his grip on the pistol and I push it away. It slides across the white tile floor but my eyes don't follow it.

I'm focused utterly on his face, which reddens as I tighten my grip on his trachea, now using both hands. He struggles to break my grasp, but he's weaker than me. I had to train in the gym every day for a year to finally pass my physical to become a fire fighter.

His eyes bulge. Sweat erupts from his every pore and the scent of urine grows strong. Does he understand what's happening? Does he understand who I'm killing? Does he know he's the ghost who haunts me, the man who might have been, and I'm sick of his damn face?

Tears well in his eyes. I keep squeezing.

My hands have grown numb by the time his body goes slack and his eyes lose focus. I still don't let go. I can't tell if his heart is beating. My own is like a drum. I hold on another minute, then another, as his face goes white, then gray.

When I at last release my grasp, the impressions of my hands remain on his throat.

I look around. I'm not in my living room. I'm in a large windowless office filled with PCs connected by about a zillion miles of red and yellow cables. There's a single door on the far side of the room. I spot the pistol where it's slid under a desk and retrieve it. I head to the door. It's locked. I go back to Bad Gordon's body and find keys in his pants pocket. But when I return to the door, I don't find a keyhole. I do spot a raised silver rectangle beside the door. On a hunch, I press my palm against it. There's a click in the door handle.

Holding the gun tight, I push the door open. The lights flicker on in the hall beyond. From somewhere down the hall around a corner, a man says, "You're back. You've failed again, I'm sure. Are you ready to listen to reason?"

I glance back at my dead double. A chill runs trough me as I grasp the situation. I'm in his world. I'm in a world with no Kayla, a world with no Daniel. I have to get home. Putting on his belt and pushing buttons at random seems like a risky plan. Like it or not, I need to confront whoever's around the corner. He sounds like he knows my counterpart. Maybe he knows how to use the belt.

I cautiously step forward. I turn the corner with the gun held before me, steadied with both hands. I find myself pointing the gun toward iron bars, like a jail cell. Beyond the bars there's an old, bald man sitting on a cot. He's wearing a lab coat and has a short beard, pure white.

He looks confused as he stares at the gun, then at my face.

"You're a different Gordon," he says.

"Who are you?" I demand.

"I'm a different Gordon as well," he answers. "From the future."

"What are you doing here?"

He stands up. "Let me out before he returns. I'll explain when we're safe."

"The guy you're afraid of isn't going to hurt anyone ever again," I say. "But I'm not going to open this door until I know who you are."

"Very well. As I said, I'm you, or a version of you. Perhaps, like the Gordon who captured me, you've specialized in the study of parallel universes. I applied my intellect to the manipulation of time. The Gordon who imprisoned me intends to take over the life of one of his alternate selves, desperately seeking to escape his unhappiness. I share his unhappiness. In my world, I've driven away anyone who ever attempted to love me, at first with my youthful arrogance and superiority, later with my single-minded focus on my research. It's too late for me ever to form an emotionally satisfying bond with others in my own timeline. But, by returning to the past, encountering earlier versions of myself and warning them of potential pitfalls, I hope I can help at least one version of me find the happiness I squandered."

"You're as crazy as he was."

He nods. "Except I'm not malevolent. I've turned my intellect to altruism."

I study his face. He looks sincere.

"Do you know how to operate Bad Gordon's belt? Can you send me home?"

"I've no doubt that I could," he answers. "Bad Gordon, as you call him, was keenly interested in my time travel technology. I held from him the full secrets, but in answering his questions I was able to pry from him details of his own technology. I know how he programmed his dimensional coordinates. It should be simple to retrieve your world's parameters from the belt's memory and send you back."

"Good enough for me," I say, placing my hand on the lock pad next to the barred door. There's no click.

"I have the same handprint," he says. "Bad Gordon used a physical key to open the door."

"Then we're in luck," I say, reaching for the jiggling key ring in my pocket. I try four keys before finding the right one.

Old Gordon shakes my hand as he exits. "I'm in your debt."

"Consider the debt paid by sending me home."

Old Gordon heads down the hall back to Bad Gordon's lab. He shakes his head as he spots our doppelganger's corpse. "I warned him that his schemes would come to no good. He'd either find a version of himself more villainous, or more valiant, and be unlikely to survive the encounter." He looks at me. "I hope you're the more valiant variety."

"I don't know if valiant is a word I've ever applied to myself," I say, kneeling over Bad Gordon to remove his belt. "I'm just a guy who wants to get back home to his kids."

Old Gordon raises his eyebrows. "Kids? You're married?"

"Not anymore," I say.

He sits down at a workstation and begins tapping keys. I watch him in silence. He starts looking in desk drawers until he finds a flash drive.

"You have PCs in your timeline?" he asks.

"Of course."

He pops the flash drive into a port on the workstation. He clicks and drags with a mouse. Thirty seconds later, he removes the drive and hands it to me.

"Here," he says.

"What's this?"

"A time key," he says. "It's a self-constructing code for a virtual time machine. Plug it into any PC and it will assemble itself. It will allow a onetime alteration in your timeline. With it, you can undo the biggest error of your life, whatever that may be."

"Won't that create a time travel paradox?"

"Yes. But the paradox is resolved by the creation of an alternate universe. Though you'll remember your true past, you'll move forward in a universe where you've avoided your worst error. You'll live a happier life."

I take the flash drive from him, staring at it, as he takes the belt from me. He studies the belt a moment, punches a few buttons then says, "Ready. Let's get you home."

"How do I know what my greatest mistake was?" I ask.

"Do you have so many to choose from that you truly don't know?"

"I've a lot to choose from," I admit. "But . . . every mistake comes with its own reward. Suppose I had never cheated on Beth --"

"You cheated on Beth?" he asks, astonished.

"If I'd never cheated on her, Kayla wouldn't have been born."

"Perhaps. But perhaps you would have had more children with Beth, in a more emotionally sound environment."

He dons the belt and comes to my side. "Give me your hand."

I grasp his outstretched palm. I blink and find myself back in my living room.

"Is this the right world?" he asks.

I walk to my bookcase and pick up the picture of Daniel and Kayla from last year's Halloween.

"Yeah," I say. "This is the right world."

"Then I must return to dispose of Bad Gordon's equipment. It would be quite dangerous if it fell into the wrong hands."

"Right," I say, only barely paying attention as I study the photograph closer, the way Daniel's smiling, the way Kayla looks so excited. It makes my heart hurt to look at it, knowing that there's so much joy in my life, yet it's so constrained, always coming to me in tiny slices. Could I have constructed a life where I was always surrounded by such joy? Is there a single moment I could have changed, a word I could have said, or not said, a door I could have walked out of, or into, a single step that would make everything perfect?

Perhaps. Perhaps not perfect, but better.

I turn around and find Old Gordon gone. I wished he'd stuck around. I'd like to talk about the choice I'm making.

I told Bad Gordon that Beth hadn't been easy to live with. We fought all the time, but I was a willing combatant. I resented her for making me choose between her and my education, and made her the walking embodiment of every unhappiness I felt. Still, she stayed true to me, was willing to fight for our marriage rather than walk away, right up until the moment I got another woman pregnant. That was the sin she couldn't forgive.

If I had to do it all over again  . . . it wouldn't be so difficult not to cheat, knowing all I know now. It wouldn't be so difficult to hold my tongue instead of shouting about how she'd ruined my life, or to tell her how much I appreciated the moments of tenderness she could show me, to let her know how much I cherished it when she smiled at me. I think, with a little hard-earned wisdom, we could make it work. She and I and Daniel could live happily ever after.

But what about Kayla? It would break my heart to live in a world without her.

Perhaps that world can't be avoided. She's in my life only because her mother respects the court order. But Sabrina doesn't respect me, and as Kayla grows older and grows more curious about her history, it won't be difficult for Sabrina to shape the narrative to poison Kayla against me. Could I bear that?

Could I avoid that?

I walk into the kitchen, staring at the flash drive, thinking about what it contains. I remember my dreams of a time machine, my own youthful designs. In the back of my mind, my time machine begins to assemble itself, growing larger, more defined, until the machine in my mind seems solid enough to touch.

It would be so easy to step inside and go back.

I lean on the sink as I stare at the hand that holds it, my own hand. I've scars on the back to the wrist from once punching a hole in drywall after a fight with Beth. My knuckles are lined with deep wrinkles. I'm getting older. The photographs on my bookcase are a monument to the unstoppable advance of years. Kayla's not a baby anymore, Daniel's halfway to manhood, I'm middle-aged when only yesterday it seems I was sixteen. My body is a vehicle with no brakes, plunging non-stop into the future.

The flash drive gives me the chance to make U-turn. But Kayla shouldn't have to pay for my mistakes. She's alive, and I love her, and I'd rather see her grow into a woman who hates me than to let myself think of her as some mistake I should have avoided. Maybe I should keep the flash drive for some future tragedy, insurance against car wrecks or house fires or further foolish liaisons?

I drop the flash drive into the garbage disposal, turn on the water, and flip the switch. I can't take the chance. I can't take the chance that one day I'll have a very bad day and be tempted to go back, back before Kayla, back before Daniel even. I'm wise enough to know I'm capable of foolish choices.

For a long minute, a horrible grinding sound rises from the sink. I turn off the disposal and the silence nearly overwhelms me. Above the almost imperceptible hum of the fridge I hear the pump pump pump of blood in my veins, a muffled metronome measuring out the moments of my life, as time goes onward, ever onward, ever onward.

I return to the living room and smile as I study the photographs. I pick up a frame filled with all that I most cherish in life and know I've made the right call.

The machine in my mind would have been an utter waste to build. I was born into a time machine.

It goes the only direction I'd ever need to go.