Ursa Major got right the fuck out of our universe on the very afternoon she learned there were other options. It was the lucky break of her life that she just happened to be there, a short sprint from one of those points where the alien aethertrain briefly punched through into our world: a multidimensional mechanical worm intersecting our reality as a rush of vaguely boxcar-like shapes strung between entry and exit portals, thirty-odd feet above one suburb or another, a cornfield, a strip mall, a stadium. Ursa left with neither a second thought, nor the thinnest inkling of return, nor the name and gender her parents had always tried to hang on her, nor anything else she couldn’t cram into a backpack and still have room for the purpose-bought spool of rope and grappling hook by which, after several tries, she finally snagged one of those boxcars (for want of any other earthly concept to describe them) and held on for dear life.

She had one regret. It was not that she hadn’t bothered to ask whether there was breathable air in whatever weird multidimensional space the train was heading into. It wasn’t longing for anyone or anything she was leaving behind in our world—not even me, and I don’t begrudge her that. No, her sole regret was that in the instant the hook caught and the rope went steel-taut and she careened away into the multiverse on the alien aethertrain’s relentless momentum, shock and reflex took over and denied her the presence of mind to flip this particular version of Earth the bird, once, hard.

She was seventeen. She was my best friend, my sister in arms through the worst of middle and high school. I was the only person she told her true name before she left, and I’ve missed her terribly. I couldn’t follow where she went; instead I’ve made myself her distant biographer: collecting all the eyewitness sightings, second-hand anecdotes, and muttered rumors I’ve been able to get my hands on through the years. I will do my best to summarize.

• • • •

Ursa Major—as she named herself long ago, but only called herself since she left—discovered that the hardest and strangest aspect of her journey would not be finding food or water or supplies, nor navigating the sprawling interdimensional web of tens of thousands of trains and their meandering routes among ten billion different versions of Earth; it would be connecting with the strangers she met on the boxcar roofs.

They were the same sorts of people she’d known here in our universe, and at the same time unreconcilably different, as much from us as from each other. It took her time just to learn how to focus her eyes on these people, the denizens of the ten billion utopias. They came in every size and shape and skin color and tattoo pattern, yet Ursa perceived virtually all of them as kind and painfully earnest people who would ask her (in the multiversal language of the utopias, which is perfectly comprehensible—but extremely off-putting—to our ears) why she’d grappled her way onto the aethertrain in the first place.

They meant, innocently, why had she not simply waited for the train to stop so she could board it normally, not knowing that it had done no such thing when she saw it. But Ursa took them to be asking why she’d left here at all—and she had resolved to never think about our Earth if she could help it, so she made up a rhyme she could memorize and recite on command like a mantra, without conscious thought:

Lead in the water, kids in a cage,

Oceanic garbage gyres and deadly climate change,

People dying knee-deep in medical debt,

A killer viral plague, the nuclear threat,

Murder at the hands of racist police,

Armed fascists marching while the president tweets,

Racist sexist ableist trans- and homophobic hate,

Solitary torture in the carceral state,

The song went on like this for four or five minutes. When Ursa had finished, the people she’d just met would often go quiet and stumble off in a daze; if they stuck around, she would casually ask them what had brought them aboard the train, and they’d usually duck into their clothes like scared turtles and mutter something like “It’s for my thesis” or “I just like adventure” or “I wanted a change of scenery.” And when Ursa would ask, “What, ain’t your world ending?” they would blink a lot and stammer things like “No” and “Of course not” and “Why would it be? Do you know something I don’t?”

When Ursa Major first met Calliope, it was different. In Ursa’s eyes Calliope was a seven-foot-tall demigoddess, so statuesque and irresistible that, against all sense and social anxiety, Ursa decided to take the initiative and ask the apparently-standard question first.

“I’m on a quest to truly hear the music of the multiverse,” Calliope answered, fingering a necklace of five large, intricately carved beads. She said each one stood for an Earth whose music she had truly heard—though she couldn’t articulate in multiversal language what constituted “truly” hearing a universe’s music versus merely listening.

“You know it when you’re truly hearing,” Calliope said. “It’s important.” She took in the silence for a while, her eyes turned toward the glittering void, and finally asked, “What about you? Why did you leave your universe? You ever going back?”

All Ursa had for ornamentation were the patches ironed onto her frayed army surplus jacket, plus some of the train’s machine grease for eyeshadow. She shrugged and sang her rhyme about our universe—but Calliope didn’t respond the way Ursa had expected. Her brows knitted. She turned pensive. When the rhyme was done, she asked a lot of questions.

Then they parted ways, naturally expecting never, ever to see each other again—figuring that the odds of an unplanned reunion in the multiverse were something close to one in ten billion squared—and still Ursa woke up the very next morning to find herself gravely smitten. The air in her lungs had turned cool and electric, and each ventricle of her heart ached independently with the certainty that her indestructible love for Calliope had been born there, in the glittering void of trainspace, because she had been the first person to listen to the whole song and make a serious attempt to understand its lyrics. Because her response had been neither doubt, nor shock, nor sympathy, but something Ursa could much more easily trust and understand: pure dread.

But what could Ursa do? Nothing. (No more than I could do back here, staying up nights to lie on my back in the grass, knowing Ursa could not even be staring at the same stars.) So she gazed out into the infinite multiversal expanse and kept herself warm with the thought: even if I never see her again, she’s out there being incredible, and that’s enough. It has to be.

• • • •

It took Ursa a long time to wrap her mind around the fact that most universes—at least the ones the train lines connected to—were not fucked up. They were, in fact, so very far from fucked up that the people who called them home could never make heads or tails of what Ursa told them about our Earth. Who is this diamond forged in hell? the foolish utopians whispered among themselves, in admiration and vicarious terror. What awful misdeeds have her flashing eyes beheld, her scars recorded, her iron heart withstood? What force in the multiverse could stand against her? None. The answer was none.

Ursa quickly picked up all the tricks of boarding and deboarding, then improvised a slew of her own that scandalized even the most experienced riders. She could sling a rope between two parallel moving trains and slackline across before their tracks diverged, using a pole for balance, and with that same pole she could vault her way into a train passing on the line above. She could sprint along the cars’ rooftops and jump and tuck and roll and come up sure-footed in the red or blue or gold or black grass of a brand new universe, and just as easily grapple her way back onto the train whenever she chose—while the frightened onlookers who spread her legend looked on and whispered amongst themselves that Ursa could do these things because the trials and torments of our brutal Earth had broken her of all fear of death.

Pretty soon she’d cultivated a uniquely flawless knack for knowing when the next train was coming and where to catch it. She knew all the trains’ ways better than anyone, because this was another thing to know about Ursa: she didn’t particularly care to ever get off the ride. She hopped down into one world or another just long enough to accept free food and water from delighted strangers, and maybe allow herself one good sniff of clean and fragrant air, and one good look around—at the silver city, the rose quartz village, the pristine forests and ice-capped mountain peaks and trashless oceans and smogless skies—before grappling her way back up on the next passing line, only to find herself sharing a boxcar with another cheery dilettante, still queasy with the indescribable multispatial motion sickness to which Ursa had long since become permanently immune. How could Ursa but distrust their smiles? How could she accept, except by vital necessity, the generosity of utopian strangers, without worrying (as anyone from a shit universe would) that it was a poison ploy?

But after riding the aethertrain for most of a year, she still thought of Calliope with her hand-carved world-beads, listening and believing and knitting her brows in concern, looking back nervously before hopping off into the next universe in her quest for music—and Ursa hoped against all sense and probability that, somewhere between the ten billion happy universes touched by the aethertrain lines, she would meet Calliope again.

• • • •

It was around this time that Ursa Major decided to become a pirate. By then she was a truly unfathomable multi-dimensional distance away from all of us—from me—but still the ghost of this world and its horrible bullshit haunted her and kept her up at night. It had dawned on her that, however well she knew the aethertrains, she could not trust them to never take her back here—not unless she steered one herself. For that, she had to take one over. At that point, she might as well call herself a space pirate of the multiverse. For that, she needed a crew.

Finding prospective candidates wasn’t too hard, at least: by then a lot of people riding the alien aethertrains had heard one version or another of Ursa’s legend, and ears pricked up wherever she breathed her own name.

The legends said a lot of things about Ursa’s universe—that is to say, ours. They said the train’s brief excursion into our world had been a fluke, a grave mistake on the part of the mysterious and unseen conductors. They whispered rumors that an unlucky or uncautious traveler might accidentally fall down into our world, the world that should’ve crushed anyone—should’ve crushed Ursa, should’ve crushed you, should’ve crushed me—and yet there were a lot of people in the ten billion utopias who wanted to learn Ursa’s ways, who coveted her toughness and romanticized her determination—and although not all of them initially understood what a pirate was, all of them were enraptured by Ursa’s descriptions of them.

So she had them all fashion matching crimson-red bandannas, and then they all boarded a train and crept from car to car until they reached the inscrutable engine at the front and its little door.

Ursa jimmied that door open and went in alone. Rumors later spread that she had met one of the aethertrain’s unseen alien conductors, fought them for the controls, and threw them overboard—but the truth is that no one else saw what happened, and no one asked. The next thing anyone knew, the train was theirs to command. They could start and stop it at will, and steer it down any bend they saw fit in the infinitude of fractally-forked tracks drawn out across the glittering purple abyss of trainspace. The pirates painted all their boxcars crimson, and anyone who saw it whoosh through their universe embellished the hair-raising fictions that surrounded it. Many of those tales found their way back to my own delighted and hungry ears, my frantically scribbling pen. Some of them even found their way to Calliope, away on her multiversal quest to hear other worlds’ music.

Imagine Ursa’s shock and surprise, her terror and delight, her sublime triumph over the unfathomable enormity of the multiverse and all the forces of probability, on the day she turned around to find Calliope right there behind her, waiting in line for the same burrito stand. It had been another year and change since Ursa Major had crowned herself queen of the hobo space pirates. By then she’d picked up a lot of the universal language of the ten billion utopias, and she was brimming with hope: this time, she thought, they could get into sharing subtle and complex understandings. This time they could really talk.

“Hey,” Ursa said. “Remember me?”

Calliope knotted her brows: fully recognizing her, but unsure for other reasons. “Did you really take over an aethertrain by force of arms?” she asked, her head turned toward the spot in the sky where the big crimson train was parked. Her now twenty-odd beads crackled with the motion.

Ursa was so struck by the beauty of those beads, the joy of seeing them again, all the wisdom and wanderlust they stood for—and, yes, by Calliope’s staggering height and statuesque shape—that she scrambled instinctively for something, anything, to make herself sound half as impressive. She foolishly struck a pose and puffed out her chest a bit and said, “That’s what they say, isn’t it?”

To her dismay, this did not impress Calliope. It only seemed to turn her inward. The seed of a grim epiphany was sewn in Ursa Major’s mind then—watching, helpless and tongue-tied, as her crush of more than two years collected her burrito and walked on without a look back, putting an end to their miraculous and improbable encounter—but the seed was not to sprout until later that day, when her second officer (several years her junior) noticed her pensiveness and perched beside her at the front of the aethertrain.

“Hey Ursa,” the kid said. “Hey Ursa. Hey Ursa. Ursa. Ursa. Ursa. Ursa. Ursasasasasa. URSA.”

“What?!” Ursa shouted. She was about to remind the kid that she was his captain, and that captains weren’t supposed to be bothered—and, in any case, a pirate of his station was not supposed to speak directly to his captain but rather go through the proper channels, namely the executive officer—but before she could yell any of these things, the sharpness of her own voice echoed back distorted from the aetheric envelope around the train, and her heart sank.

She apologized to the kid (and to his mom, who was also the XO) and dried his tears. She rallied the pirates and told them to forget everything she’d ever said about the chain of command. From now on there would be no hierarchy, no unthinkingly emulating the very power imbalances that had driven her to flee our universe in the first place—for Ursa Major knew she had fallen into the trap of thinking of herself the same way her crewmates did: as someone made strong by her wounds, instead of by the toilsome and lifelong work of healing them. And Ursa Major, like anyone here in our version of the Earth, had some fucking serious wounds.

• • • •

They continued to call themselves pirates, although they never technically robbed anybody. Soon they even abandoned the practice of melodramatically grabbing and running away with the provisions they were freely offered by the denizens of the universes they passed through. Among the riders of the crimson train, three traditions were maintained: the shouting of “ARRRRH”, the teaching and continuous refinement of Ursa’s aethertrain parkour moves, and the practice of piloting the train wherever the hell they collectively desired. For one reason or another, the legends surrounding their train attracted a high concentration of jugglers and fire dancers, who, in turn, attracted musicians, who attracted a great deal more musicians—until, over the course of another year or two, the crimson aethertrain had grown into a self-contained traveling festival. This, in turn (defying all of Ursa’s cultivated resignation that she had missed every possible chance to ever see her crush again), attracted Calliope.

She found Ursa perching at the roof edge of an empty boxcar, just at the edge of the shimmering poi light’s reach. She sat down there a polite distance away, the fifty-odd beads of her necklace rattling with the movement. Ursa didn’t look up. She just kept staring away into the glittering purple abyss of other universes.

“Looking for something?” Calliope asked.

After a time, Ursa said, “The more I travel, the more I get to know myself, the more I find something in me that reminds me of my own terrible universe that I never want to go back to.”

“Have you talked to any of the others about it?” Calliope asked. “Might help to have someone around who really gets it.”

Ursa Major did not ask who Calliope was talking about. Ursa only knew she had to finish the thought now, or she might never have the guts or the opportunity to try again, so she said, “I keep staring out across all the different Earths and thinking, somewhere in these ten billion utopias, maybe there’s another me and another you. The other Ursa Major is just like me except she’s a utopian herself, and her head isn’t crammed full of baggage, and she can wear her heart on her sleeve and just tell you—the other you—she likes her something awful, and has for years. And the other Calliope is identical to you, except that she likes this hypothetical other me back. That’s a universe I’d like to find, once. Just to know it’s out there.”

Calliope grinned and started to say, “You like me?” But instead she caught herself and asked, “What’s the story of you taking over this train? Did you really fight a conductor and throw them overboard into the abyss?”

“What?” Ursa chuckled. “Fuck no. Is that what you heard? Is that why you ran away at the burrito stand?”

“Yeah.”

So Ursa rubbed her eyes and told the tale for the first time: how she’d popped the lock on the cockpit door, and the person inside had had silvery-bluish skin and giant black eyes, and Ursa had been a little spooked but had found the breath to say, “Listen up, I’ve come to take over this alien aethertrain.”

“We’re not aliens,” the conductor said. “We’re just humans who’ve been human for an unusually long time.”

Ursa couldn’t help but ask what generations of utopians had shyly wondered: “So why build the aethertrain? Why run it between the ten billion utopias?”

“To help people contemplate true beauty,” the conductor said.

Ursa squinted in thought. “Then why did it ever roll through my shitty universe?”

The conductor tipped their chin at Ursa and said, factually, like a bored scientist, “Because you are truly beautiful.”

Without another word, the conductor had handed Ursa Major the key to the engine, and then vanished.

Hearing this, Calliope kissed the top of Ursa’s head and said, a bit sheepishly, “They were right. The conductor, I mean. About you.”

“Do you want to—”

“Yes,” Calliope said, pouncing.

• • • •

“Tell me about the universes you’ve traveled to,” she said, by some universe’s morning light.

Ursa said, “Which? I might’ve been to all ten billion by now.”

“Not through—to.”

Ursa realized then—and the very shape of her silence revealed this realization to Calliope, too—that the answer was none. For all the years since she left us here, the journey had been her only destination: the aethertrain and its all-surrounding glittering purple void.

So Calliope rolled her eyes and by touch picked out one bead in particular from her necklace. She took Ursa’s hand and pulled, and by unspoken agreement they navigated from one train to another, a week of travel just to find their way back to the exact universe that bead remembered. They hopped off the train under evening light, and Ursa and her new love climbed down some stone steps into the first hole-in-the-wall music joint they came across, and Calliope sat her down and bought her a drink and told her to wait.

“This Earth feels different from the others,” Ursa couldn’t resist pointing out. It was in the way people moved, in the spaces between their words, in their eyes: a quiet, mercy-flavored relief; a trace of ancient and lingering exhaustion. Ursa said, “Feels weird here.”

“This was a shitty universe,” Calliope said. “Only a few generations ago, it was a lot like yours. You can still hear it in their songs.”

“But it’s not now? That doesn’t make sense.”

“Why not?”

“Because,” Ursa told her, “Utopians are different. They’re made of different stuff. They come from universes where the grass is pink or gold or purple, their brains are wired different, I don’t know.”

“But you must know every one of the ten billion is no less different from every other than it is from yours or mine.”

Ursa cringed with the memory of our Earth, took a gulp of her drink, and said “My Earth must be different in a different way, then. Mine is way too fucked to ever be this perfect.”

But Calliope told her the secret then: a universe doesn’t even have to be that good to be perfect. There is no Earth in which the human condition includes no sadism or selfishness, where altruism need not battle greed, hearts never get broken, stomachs are never empty. Utopia is a process. Just any place where the struggle is always happening, the work is getting done, the old wounds are healing, the empty stomach never starves—and that process unfolds sooner or later in every universe, Calliope insisted, because at the end of the day it’s the only thing that makes any damned sense.

“It can’t be that simple,” Ursa protested. “It’s unimaginable.”

“You have more than enough imagination to reach that far,” Calliope said. “You just spend it all on bare survival instead. Even now.”

She put her finger to her lips as the lights dimmed. There was no host. An old velvet curtain simply parted on a lone man with a piano-like thing. He pressed on the keys and softly sang.

Ursa sat and sipped her drink and waited, wondering what was supposed to happen. And then it did.

At first Ursa thought the music had changed. Not, not the music, but her ears. Not her ears, but the auditory cortex of her brain. No—still deeper. The rest of her stopped, and now there was nothing in the whole grandness of the multiverse except that song—and inside of it, held in its rhythm, truly hearing it, Ursa suddenly knew this universe. She knew what its people were about and where they’d come from. She knew the colors of its skies and the touch of its weather.

And she knew, just as surely, that this universe was not hers—not ours.

When the song ended, Ursa looked at her love in the darkness.

“Say what you’re afraid to say,” Calliope said.

“I have to go back,” Ursa said. “I have to take what I’ve learned out here and go back to my Earth—for my old best friend who probably misses me, for everybody else, too, even though there are a lot of pretty hideous ways to get sad and die there. But that’s not what I’m afraid of.” She gathered her strength to ask, “I finally found you, after all these years. I don’t want to throw that away.”

“Then don’t. Invite me along.”

“You’d really go with me? Even into a universe of pure shit?”

Calliope paused in thought. “Depends. Is there music there?”

“The best.”

Calliope downed the last of her drink and said, “Cool. Let’s go.”

Ursa Major looked up from their kiss because she heard a sound. It was like no music that had ever echoed across the purple abyss of stars between universes. No sooner could she ask where it was coming from than she knew: it came from within, ringing her bones like bells. It was coming from all of them at once, calling them back together. And by them, I mean—

Look, I know I’ve been talking about Ursa Major the way the utopians did, as if she were one-of-a-kind—and to me she is, always has been, always will be. But I also cite her as only a single example, for she was only one of thousands who left our universe on that same afternoon. They went by grappling hook, by trampoline, by ladder: unknown to each other yet siblings in despair, powered by the same fuck-everything urge to discover the hard way what lay on the far side of those portals. Each of them found indestructible love: whether for their own Calliopes, or for new friends and families, or for smogless skies that could as easily be ours.

Now they’re riding the aethertrains from every corner of the multiverse—riding them straight toward us as fast as the fractal tracks can carry them. Their new accomplices are at their sides, fearless and ready, and in their hearts grow the seeds of a brand new utopia, numbered ten billion and one. Friend, they are legion. They’re coming. They’re here.