You never expect to meet one of the refugees. You aren’t a scientist or a politician, you’re a middle school history teacher. The story of the refugees from a destroyed parallel Earth—security camera footage of dozens of bedraggled people appearing through a shimmering section of air not far from Cheyenne Mountain in Colorado—should fade into the background of your life like every other major news story and tragedy, present but mostly forgotten. So much bigger than you that it doesn’t feel entirely real. Instead, your doorbell rings six months later and when you open the front door a dark-haired woman stands there who you don’t recognize, but who looks at you with an expression of such naked joy that you brighten instantly and feel an urge to hug her right there on the spot.

“Have you met me?” she asks without preamble. “You’re my husband.” Which is one hell of an introduction. On another Earth, you were this woman’s husband, left behind when the world ended. Wiped out of existence with the rest of her old universe.

You get the sense that Rachel would gladly bring you to town hall and get married right then and there, and the idea holds a certain appeal—you’ve never felt confident connecting to anyone, let alone a woman, and you’ve been alone for so long, you’ve begun to doubt you even know how to talk to people anymore. Your anxiety always overcomes you, making you worry about sounding stupid or giving accidental offense, spurring endless second-guessing and apologies until conversation and connection withers away. Your therapist, when you still went to see him, told you this is in your head, that if you live in the moment more you’ll experience things differently, better. So, you invite Rachel in for coffee. Which, at her suggestion, turns into a few fingers of rye whiskey because this is a pretty mind-blowing development and you both figure the liquor will steady you. It doesn’t occur to you to wonder how she’d know you drink rye, but when you think about it later you aren’t surprised.

There’s no kiss that night. It isn’t love at first sight. That heady combination of curiosity and feeling desired creates a different emotion, one you’re never able to name, even years later.

• • • •

You’re late for your fifth date, a car accident delaying you by almost half an hour. Flustered, you burst into the Italian bistro Rachel suggested, find her seated in a corner booth, bottle of wine and two glasses already on the table. She pours as you sit, smiling away your apology.

The two of your clink glasses, and as you sip the wine, you notice Rachel watching with anticipation. “It’s delicious,” you tell her. “What kind is it?”

“Montepulciano.” Rachel observes the wine swirling in her glass. “Luckily, this vintage was a good one here too.”

You smile shyly. “I don’t really know much about wine.”

To her credit, Rachel hides her surprise well, though you still catch it.

“Did your husband know a lot about wine?”

“We shouldn’t . . . We don’t have to talk about him,” Rachel says, but you tell her it’s okay. That you don’t mind, even though your heart puckers. He was Rachel’s true love, and you worry you can’t live up to him. It’s not as if she’s talking about some high school boyfriend.

“He did,” she says. “He introduced me to wine, and I got so interested in it that pretty soon I knew even more about it than he did. From a scientific perspective at least. He was always better at the intangibles. Bouquet, picking up flavors.”

“He sounds . . .” You don’t actually have any response. For a long, awkward moment, neither of you speak, and you fear you’ve blown it. Now you’ll be alone again.

Rachel reaches across the table and wraps her fingers around your wrist. “I’m really enjoying getting to know you.” A subtle but unmistakable emphasis on that last word.

“I’m glad you found me,” you say. And then, because you’ve wondered, and this feels like it might be the only time to ask. “Have you looked for yourself? Here, I mean, the other version of you.”

She shakes her head. “We’re not supposed to do that.”

“You weren’t supposed to contact me, either.”

“True. And my case worker was not pleased.” She rolls her eyes. “This world’s version of me? I don’t care. I know we didn’t follow the same career path, or I would’ve met her already. She’d probably disappoint me, to be honest.”

Three months later, Rachel and you do find yourselves at the town hall signing a marriage certificate. Five years pass and sometimes you believe that you’ve both slipped into that other Earth, that you really have been her husband all along.

• • • •

Rachel works as a quantum physicist, contracted with the government. When colleagues or people at dinner parties ask you what that entails, you laugh self-deprecatingly and say, “Oh god, I could repeat the words she’s said, but I have no idea what they mean.” Something related to parallel universes. Contacting them or peering into them or harnessing the excess energy they leak into our own. Some combination of all that. Your liberal arts brain can’t hold onto all the jargon, all that science stuff.

You ask Rachel one night, sitting on the couch together in your living room. Neither of you has bothered to hang anything on the walls. “What do you actually do? What’s the goal? What does the government want from you?”

She mulls it over for long enough that you wonder if she might not answer, but finally, carefully, as if unsure what she’s allowed to admit, she says, “We’re trying to replicate the experiments I did back in my universe. To see what other universes are out there. And . . . and to see if mine still exists.”

“It . . . there might . . .?” A lump rises in your throat, and you try to swallow it, but can’t. Panic. Heartache. “Do you . . . if it is still there, would you go back?”

“No! God, no.”

“You wouldn’t be tempted to look for him?” You try to avoid talking about her original husband, the other you.

She shakes her head. You feel relieved, a minute loosening of the pressure on your heart. “If there’s anything left, it’s all chaos and destruction anyway. The universe might technically still exist, but I doubt anything’s alive in it.”

This answer doesn’t comfort you.

• • • •

Before Rachel plummets into her work completely, the two of you take a vacation to Puerto Rico. She knows she will be away from home for long hours, working intensely. You can spend some time together, just the two of you.

Sipping tropical drinks on the beach, eating mofongo in Old San Juan, taking a nature tour through the El Yunque rainforest. You feel so comfortable with your wife, your fingers intertwined like on those earliest dates, when hesitancy blossomed into confidence. You think the two of you kiss more over those ten days than every other day of your marriage combined.

You return home refreshed and infatuated. It isn’t until a week later, Rachel late getting home from her laboratory, that you realize how strange it is that Rachel knew her way around the island so well. You had thought of the trip as a honeymoon before her research project ramped up. But maybe once, for Rachel, Puerto Rico had been a honeymoon of a different sort. You wonder which trip was better, how often she compared this trip to her first time sitting on those beaches, hiking that rainforest.

You don’t ask her. You think you’d rather not know.

• • • •

The work is so important, Rachel says. It could change the world. It would be almost impossible for a discovery of this magnitude not to change it irrevocably. Surely, you’ll understand. You won’t complain when she’s away for days on end, coming home for just long enough to grab a few changes of clothes. Not even to shower because she’ll do that at the lab. She can’t or won’t explain what she’s working on, why it’s so important, how it will change the world. Whether that change will be for the better or worse.

You wonder if the other you ever complained.

You do what you promised yourself you’d never do. You go online, search her name. Scroll the results, scour social media profiles, examine pictures. You find her. Your wife. This Earth’s version.

She doesn’t live far away, and if she’s anything like your Rachel, she won’t mind you showing up on her doorstep unannounced.

• • • •

It’s a four hour drive each way. You’ll probably have to spend the night in a motel, but you suspect Rachel won’t notice. Before she left this morning, she told you the team is close to a breakthrough, that they’re perfecting the technology from her Earth, fixing what went wrong. You understand this to mean that she’ll be in the lab for at least the next forty-eight hours.

Despite your straightforward plan, you can’t bring yourself to knock on Rachel Two’s door. It feels too presumptuous, an invasion. What if a husband answers? A child? What if she answers, but thinks you’re a crazy person? Your Earth’s versions of the refugees were never informed about their doppelgangers—an attempt to ensure privacy for both parties. Maybe she’ll assume you’re a stalker. Sitting in your car, parked three houses down from Rachel Two’s address, you check your hair in the rearview mirror, adjust your collar, attempt to look as sane and nonthreatening as possible.

Unable to bring yourself to knock on Rachel Two’s door, and realizing there’s a limit to how long you can reasonably sit in your car without drawing suspicious neighbors, you drive to a motel. Check into a room. Rack your brain for other ways to introduce yourself. Nothing comes to mind that isn’t creepy. You lie down and stare at the ceiling. Morning comes. You must have dozed off. Defeated, you head to get a coffee before driving home. You fumble your overstuffed wallet trying to extract your credit card. As you bend to pick it up, you hear a gasp, and turn to see Rachel. The one from your Earth. Rachel Two. Staring at the picture of you and your wife that holds pride of place in your wallet’s center panel.

• • • •

“It’s a lot to wrap my head around,” Rachel Two says. She hasn’t taken a single sip of the latte you bought her. Skim milk, no sugar, same as your Rachel. “The me from the other Earth—the destroyed Earth—she found you, but didn’t want to find me. Like she was—what? Blocking me from meeting you? What would’ve happened if you met me first?”

You’ve wondered this more and more since Puerto Rico. You shrug and finger the disposable lighter in your pocket. Smoking appalls you, but you carry the lighter for Rachel’s cigarettes. She always says she’s going to quit, but when she’s stressed, one miraculously appears between her bitten-nailed fingers. Though Rachel Two must be at least as frazzled as you are, she doesn’t smoke during your hour-long conversation. Not the faintest whiff of stale mucky smoke wafts across the table from her clothes or hair. Here’s a difference, you think. Already, this woman is not the same as your wife.

You inhale deeply. Smell only coffee and autumn air.

“It’s so lucky we ran into each other like this,” Rachel Two says, reaching out to barely tap your knuckles with her fingertips. No ring on her finger. She chuckles. “Like—I don’t know—fate.” You didn’t tell her why you were in town, and she hasn’t asked. Given everything else, that must seem like such a mundane question.

“Could I . . . talk to you again?” you ask. You hadn’t intended this, you don’t think. But really, you don’t know what your intentions were, coming out here, not telling your wife where you were going. You told yourself you needed to see, to meet this other woman who was maybe supposed to be your wife if Rachel hadn’t found you. If her world hadn’t destroyed itself, sending survivors tumbling into your own.

“I don’t know,” Rachel Two says. “It’s weird.”

You try not to appear crestfallen, but apparently fail. You’ve never been good at hiding your emotions. A lot of people seem put off by that, but not your wife. Or she doesn’t notice. Or ignores them. You’ve never broached the subject, afraid of the answer.

“Why don’t you leave me your number,” this Rachel says. “Maybe I’ll call.”

• • • •

Back home, Rachel doesn’t mention missing you. Probably because she never noticed you were gone while she was working nonstop in the lab, sleeping on a couch in her office for an hour here or there. Whatever she and her government employers are studying obsesses her, obsesses her entire team. Once, shortly after you met, when Rachel claimed she that the experience of losing everything had changed her and inspired her to give up her research, she admitted that she’d let her work consume her in her original universe.

“It spun out of control,” she said. “Everything spiraled. If only I could have controlled it, held on tighter . . .”

She wouldn’t say anything else when you asked her to elaborate, and never brought it up again. You don’t bring it up either. She may not be especially aware of other people, but she understands herself, her limits. When she gets in too deep, she’ll know. You tried to stop her when she began drifting back toward the laboratory, toward her old research. She explained it would be different, shrugged you off. Trying to drag Rachel away from a decision she’s made is a fool’s errand.

• • • •

Your wife is in the shower when the other Rachel calls you. You don’t recognize the number, of course, but your phone says the call originates in Rachel Two’s town, and you immediately know it’s her. Your throat fills with your heart, and your toes unconsciously wiggle. If it turns out to be a telemarketer, the disappointment will crush you.

But it’s not. It’s her.

“Hello,” you say. The instant you hear the other Rachel’s voice, you step from the bedroom, away from the en suite bathroom. Somewhere more private. You tell yourself you’re hiding this conversation from your wife because she wouldn’t understand. Wouldn’t get that you’re talking to your Earth’s Rachel so that you can know yourself better. Know your wife better too. She’s a physicist, and Rachel Two runs an environmental nonprofit. Both smart, both driven, but different. If you figure out why . . . But you still barely raise your voice above a whisper, tuck yourself into the remotest corner of the house.

“I’m glad you called,” you say. “It was . . . nice drinking coffee with you.”

You know this is the way affairs start.

• • • •

The rest of the world learns what your wife and her team are really studying at the same time you do. Maybe a few minutes before. You’re pretty sure you miss the first news report.

When Rachel comes home from work—early, presumably to avoid reporters and associated fallout—she drops her oversize purse on the table by the front door, fishes out a pack of cigarettes and lighter, and makes for the back porch.

“Rachel,” you say, hesitant, unable to believe she truly intends to walk right past you without a word of explanation, without even a hello.

“Please not now,” she says. “I know you hate the smoking, and I’m quitting, I swear. But the day I’ve had, you can’t imagine—”

You burst out laughing. “Of course I can imagine. I’ve been watching news coverage for six hours straight. Trying to call you too. Text.”

“I turned my phone off,” she says. “Fucking reporters won’t stop calling. I don’t know how they got my number. Probably from the same sneaky fuck who leaked the project in the first place.”

“It’s true? Rachel, it’s not true.”

Her sigh answers better than her words. “More or less.”

“More or—?” your indignation sputters. “Which parts are more and less?”

You can tell she doesn’t want to answer. She never wants to answer. The you on her Earth must have been just as scared of confrontation, equally as willing to go along with whatever anyone wants in order to avoid the wash of panic and shame that comes with being wrong. Being told you’re wrong.

“It’s not a weapon,” Rachel finally says. “Not here and not back in my universe. It never was. The connection between universes, that infinite liminal space surrounding everything, it could be such a source of power. You can’t even conceive it.”

Hurt must cross your face, because she clarifies. “No one can truly conceive it. It’s too large. That’s what I’m trying to do, what I was trying to do before—save the world, get rid of fossil fuels. Free power for everyone.”

“The government’s going to provide the world with free power,” you say, voice dripping with skepticism.

“Fine,” she admits. “But it’s a start. And the research itself—the rush . . .” She looks down like she’s embarrassed. The unlit cigarette jerks up and down between her fingers. She glances at the door. You nod and follow her to the porch, where she immediately lights up. You consider saying something, decide not to.

Rachel smokes, and you sense that she is waiting for you to ask the question on the tip of your tongue. Except you’re afraid of the answer. Afraid it will be true.

“Did your experiment destroy your world?”

“It’s not that simple.”

“Did your work kill your husband?”

“You’re my husband.”

“I’m your backup,” you snap. Later, you’ll replay this conversation in your head over and over. Mull all the different things you could have said. You’ll regret this response, and then you won’t, and then you’ll regret that you don’t regret it before finally deciding it was the right thing to say. Sometimes you need to give voice to your greatest fear.

Three times Rachel scoffs, an engine unable to catch. She shakes her head and lights another cigarette with the ember of the first, drops the butt into an empty planter. “Science is messy,” she says. “Progress hurts sometimes. My other husband understood that. He never begrudged me my research.”

“And look where he is now,” you say, so bold your stomach churns.

“Christ,” Rachel says, and throws her cigarette into the dark. While she retreats inside, you chase after the tiny orange glow, extinguishing it in the grass. By the time you get into the house, she’s gone. No note, no text for an hour. It doesn’t matter. You know she’s returned to the lab.

You stare at the blank television for a long time. Then you stare at your blank phone screen. Then you call the other Rachel.

• • • •

“No,” you say, “Rachel is the first relationship I had that lasted longer than a month.” Instantly, you wish you had lied. But you want to be honest with Rachel Two. You want her to understand you like Rachel understood the you from the other universe. Rachel Two still doesn’t know you were in town specifically to find her. You know you should confess, decide that this is the moment, even part your lips and start to speak, but she talks first.

“I’m the opposite,” she says. “A serial monogamist. One boyfriend to the next, and the minimum length was—god—ten months? And that was in college.”

“After that long, you can just let it go?” you ask.

“It’s not like it doesn’t hurt,” Rachel Two says. “Of course it does. But I feel like, if you’re miserable, why stick with something? There’s other fish in the sea, you know?”

You’re in your car, parked in the lot of a Dunkin Donuts a town away, chatting on speaker phone and sipping a cold brew coffee for the first time. You’ve never had one before, don’t see a whole lot of difference between it and normal coffee to be honest.

“I’d be too worried about making the other person mad,” you say. “I wouldn’t want them to hate me.”

“What if they already did?”

You don’t have an answer for that. You take another sip of coffee. Maybe it does taste different. Subtly, but unmistakable.

• • • •

For two weeks Rachel barely speaks to you. You still share a bed, but don’t touch in it. So, you’re surprised when she speaks to your back in the dark one night.

“My husband—my first husband—he never worried about me. He figured I knew what I was doing, that we all knew what we were doing, and he didn’t ask questions about it.”

You roll halfway over, but when Rachel clams up, you stop, allowing her to go on without fear of seeing judgment or forgiveness in your eyes.

“It took us decades to discover a way to travel between universes—I started studying as a doctoral candidate—and even then it was heavily theoretical. Crossing over to here, actually opening a portal, that was pure desperation. The world, my home, it was . . . Things were bad there. We didn’t have a choice, we didn’t have time to wait for everyone we wanted to travel here with us. My husband over there . . .” She shudders slightly, a goose walking over her grave. “I intended to do better here. With the project. With you.”

It takes a long few seconds for you to respond. What you come up with is neither soothing nor clever. “Good intentions.”

“I know,” Rachel says softly, and you immediately feel guilty. You didn’t expect her to agree with you—you never do. You think she might not say anything more, but she does. “You do know that I love you. I loved him, but I love you as well.”

There’s a difference between love and comfort, and you wonder whether Rachel knows that. You’ve wondered it a million times, lying next to her sleeping body at three in the morning, sitting across from her at dinner when she insists that you’d like lobster if only you’d try it again. Does she truly love you, or are you a familiar form she can slot into the space in her life labelled husband? This is the closest you’ll ever come to finding out, but the answer scares you so much you don’t ask the question.

“I know,” you say. “I love you too.”

You stare at the ceiling when you say it. The two of you lie silently then for a long while until you hear Rachel’s breathing steady and slow, and you know she’s fallen asleep.

You roll to the side, pick up your phone, and look up Rachel Two on Facebook. Just to see what she’s been up to since you talked last.

• • • •

One of the refugees, a man who owns a used bookstore in Prague, an attempt at moving on from his previous and parallel life, is found dead in the poetry section. Fingers sprout from his skin, his body overgrown with twisted pink phalanges. The books in the shop, once a mix of English and Czech editions, are now unreadable, the marks of ink jumbled into something vaguely resembling cuneiform. You stare at the images on a disreputable news website for an hour.

“What happened?” you ask. Is this another universe bleeding through? Is whatever happened on the other Earth happening here? You ask both Rachels, knowing that one can’t answer and one won’t.

• • • •

It gets harder and harder for the government to shut down questions about strange happenings around the world. About their potential culpability. You catch yourself sneering at a Department of Defense spokesperson, doubting that he has a clue what’s happening inside Rachel’s laboratory. Whatever is going on in there, the effects are spilling out. Let the government and Rachel and everyone else deny as much as they want—anyone with eyes can see it. When you ask Rachel if this is like what happened to her world right before everything spiraled out of control, she brushes you off. She spends almost every waking hour in the lab these days, possessed with a franticness that reads less as the thrill of approaching a breakthrough than the panic of attempting to stave off a catastrophe.

This world is ending, and Rachel will probably not be with you when it does. Her work takes precedence, the same as it did in her original universe. Why didn’t you try to learn more about her original husband? Was the jealousy and hurt really so painful you couldn’t even talk about him? You look like her husband, but you aren’t him. She looks like your wife, but maybe she isn’t supposed to be. Maybe you were meant to meet someone else. Maybe you have, it just took longer than it would have without the interference of an interloper from a parallel dimension who showed up on your doorstep and snatched away your fate.

These thoughts swirl about your head as you buy a bouquet of roses, as you pull up to Rachel Two’s house, as you ring the doorbell and wipe sweaty palms on your pantlegs.

She greets you with a look of mingled confusion and pity. You consider inventing a fake reason for the roses. You know in your heart you shouldn’t proceed with your plan. But the world is ending, and your wife is to blame, and this woman standing in front of you could have been your soulmate if it wasn’t for the mad scientist who shares your bed. Nothing ventured, you think as you profess your love. You’re not sure yourself whether you’re approaching a breakthrough or holding back catastrophe.

“That’s—we barely know each other,” Rachel Two says. “Not to mention you’re married.”

“Only because she got to me first. If the refugees hadn’t come—”

“But they did. That’s the way it is. That’s how things happened. Trying to imagine what would have happened if your life unfolded differently . . . that’s normal, but to let that dictate . . .?” Rachel Two shakes her head. “You can’t just shift the whole world to fit your desires.”

“You’re right,” you say. “I shouldn’t have shown up like this. I’m sorry.”

“I’m sorry too,” Rachel Two says, a rueful polite smile on her face as she slowly shuts the door and says goodbye. She doesn’t need to tell you not to call.

As you drive home with the radio off, you consider the multiverse, the infinite Rachels and infinite yous, the unending possibilities for love and connection. For freedom and happiness. Rachel Two represented those things for you, but maybe you projected too much onto her, thought she would be an escape hatch from the chaotic breakdown of your marriage. Rather than try to fix anything, rather than take that risk, you tried to throw away your life and start fresh. For no reason other than things got difficult and it looked like there was another option. Maybe you’re no different from Rachel, your wife, who journeyed between universes and used that opportunity to find and marry you. You saw Rachel Two as a different path than the one you’d taken, your wife saw you as the same path she’d taken. How much do you really know about Rachel Two? How much does Rachel really know about you? What the hell were you thinking?

You have hours to ponder all of this as you drive home. Halfway, you stop for gas, and when you go inside to pay and grab a soda, the teenaged cashier barely glances at you as she takes your cash and slips it into the register, her eyes glued to a small TV behind the counter.

“Something happen?” you ask, trying to catch her attention so she’ll make you change.

“Yeah,” she says, shaking her head, still not looking at you. “I don’t know.”

You clear your throat, and when she gives you the briefest flicker of acknowledgment, you say, “Change?” She hands back the twenties you just gave her, eyes glued to the TV.

A guy around your age is parked behind your car at the pump, leaning out the window of his car and honking nonstop. You wave apologetically and drive away while fiddling with the radio. Before the announcer speaks, you know what she’ll say. That they’re broadcasting the same news on every station. Unexplained phenomena occurring across the globe. Buildings winking out of existence, forests materializing where suburbs used to be. Family pets abruptly transforming into ambulatory skeletons, snapping at dust motes that conglomerate into balls vibrating with practically nuclear heat. Bleed-through from an infinite number of universes, ones where almost everything is the same and ones where almost everything is surreally different.

This is how it ends, you think, slamming your foot on the gas, trying to put as much road behind you before everyone else gets the same idea. But where would they flee to? Nowhere on this planet, nowhere in this crumbling corner of the multiverse. There’s only one person you know who might possess the knowledge and ability to escape this apocalypse. She’s done it once already.

Voices on the radio speak in tones of awe, tones of panic, tones of resignation. Eventually, they blur into background murmur, white noise accompanying your frantic drive to Rachel’s lab. You wonder about the last hours of Rachel’s universe, the last hours of her first husband. You wonder how many times different people can make the same mistake. The sun sets behind you, and you drive on. There will be another portal, another universe, another group of refugees. Maybe this time you’ll make it to Rachel before she goes. Maybe this time you’ll both be able to start again.