Smoke rose from the center of Asunder Island, marring a sky so blue and so clear it made Aurelia’s eyes ache. The sailors had been insisting for days she would see the Atrox swooping and turning overhead, if only she watched long enough, but there was no sign of the great birds.

The hull of the dinghy scraped the black beach. A sailor splashed through the shallows to pull the boat ashore and help Aurelia out. Her sealskin boots kept her feet dry, but her wool skirts were instantly sodden.

“Tomorrow?” the man said.

“Yes,” said Aurelia. “Thank you.”

He was already rowing back to the open sea, eager to be away. The ship was a dark blot in the distance, tiny and fragile as a toy.

It was a cold day, but calm for the Southern Ocean, the air raw with the stink of fish and penguins. A thin trail wound from the beach up an eroded crack in the black slope. Aurelia chose her steps with care and did not stop until she reached the top.

Asunder Island had the shape of a cat’s eye: round at the shores, split down the middle by an elongated chasm, its depths hidden by smoke and darkness. The wind carried the island’s sulfurous gasps away from Aurelia, but she could taste the fumes on her tongue, feel the sting in her throat.

In Aurelia’s trunk aboard the ship was a monograph: Observations of the Southern Ocean Atrox in Their Island Colonies. The author, Mr. Davies, would have preferred to write about penguins, but people only wanted to read about the Atrox, or so he told Aurelia when they met in London. He would talk for hours about birds, but when she turned the conversation to the Summer Star he had only laughed.

“Nonsense,” Davies had said. “What place do sailors’ superstitions have in this modern age?”

Aurelia withdrew her mariner’s compass from her satchel. It did not matter what men like Mr. Davies said. She was here, black stone beneath her feet and cold wind on her face, and he was not. On Mr. Davies’s map, the crevasse was oriented precisely north to south, but her own measurement showed a northeast-southwest trend of at least fifteen degrees. She could not make a note yet — her ink would be frozen solid — but she would record the correction later.

She tucked her compass away and took a breath to steady herself. She stood now at the north end of the island. A colony of chinstrap penguins swarmed over the western flank, but Aurelia’s destination was to the east, where a long ridge of tumbling volcanic rock led to a village. Beyond the village, perched atop a cliff overlooking the end of the world, was the observatory.

Asunder Island was by all sensible measure a terrible location for an astronomical observatory. It was too remote for regular use, and the Southern Ocean too stormy. The telescope offered little to modern star charts that better observatories could not provide. The Asunder Island observatory existed for a single purpose: as the southernmost telescope on Earth, it was the only place suited to observe the Summer Star and measure its curious proper motion.

Tucked in beside Mr. Davies’s monograph in Aurelia’s trunk was a copy of Lord Petterdown’s Celestial Bodies of the Southern Sky, which devoted five pages to a spluttering dismissal of the Summer Star’s unusual motion. The measurements had to be wrong, said Petterdown, because common adventurers and uneducated sailors had no place mucking about in scientific inquiry. Aurelia found his careless argument offensive to her sense of intellectual rigor, but enticing as well, like a challenge to a duel. She was very much looking forward to proving him wrong.

As they had been preparing for their voyage, Aunt Theo had suggested that perhaps the words also stung Aurelia’s pride, as her parents had been among those common adventurers who had stopped briefly at Asunder Island. Aurelia had brushed aside her concern. Her parents were long dead, and it was Theo’s nature, not Aurelia’s, to be more swayed by sentiment than science.

The trail to the village was rough and steep. Aurelia paused to rest and the crunch of her boots fell quiet. The sounds of the island surrounded her. There was the wind, always the wind, scouring the stone and buffeting the fur flaps of her hat, and there was the grumbling sea. But there were also faint hisses and groans, a rustle like pages turning in a breeze, the knock and clatter of falling stones.

Aurelia turned, heart pounding, but she was alone. The sounds were rising from the chasm, the gaping heart of the island.

She stepped off the trail to peer over the edge. The smoke was as thick as the murkiest London fog, and the sulfur stench was strong. To the south a crooked stone staircase crawled into the darkness.

Standing above the crevasse, smoke stinging her eyes, Aurelia was for the first time willing to believe the lurid, far-fetched tales of explorers who had ventured into Atrox colonies: underground landscapes of bottomless pits and lakes of lava, impossible cities carved into stone, wild yellow eyes glowing from towers with predatory intelligence, a thousand black wings rustling in the darkness.

An ache in her lungs reminded her to breathe. She could not stand here all day gawking at shadows, hoping to glimpse one great bird. She had work to do. She turned away.

The village was a ring of six stone huts with roofs fashioned from battered shipboards. There were no windows. Every door was shut tight. The only sign of occupation was the greasy black smoke rising from the chimneys. On the ground, discarded fish scales glinted in the sunlight. A skinny brown rat scurried into hiding.

Aurelia swallowed her revulsion. She was tempted to bypass the village and head straight to the observatory, but at this latitude, on the rising edge of summer, there were only a few hours of darkness each night, and it would be some time before the sun set. The ship’s captain had warned her to treat the islanders politely. There was talk among the sailors about the islanders and their relationship with the Atrox colony, sordid rumors that made the men snicker behind their beards when Aurelia and Theo approached. Aurelia had little patience for the gossip of sailors, but she would not allow their bad manners to excuse her own.

She strode to the nearest door and knocked. Something rustled inside; she leaned close to listen.

“Hello!” she called. “Is anybody here? Hello?”

“They won’t answer.”

The voice came from another building; a round face peered through the cracked door, a girl of about eighteen, pale and freckled.

“They don’t like strangers,” the girl said.

“Hello,” said Aurelia. “I didn’t see you there. My name is Aurelia Gallagher. I’ve come to use the observatory.”

The girl disappeared into the hut and the door swung inward. Her voice floated from the murky shadows. “It won’t be dark for some time. Would you like to come in?”

The inside of the hut was as squalid as the outside. The only light came from a low fire on the hearth, and the room stank of fish and smoke. A lumpy cot crowded one corner, a small table another. Wedged into the wall above the table was a plank, and on it an assortment of objects: coins, rusty nails, medicine bottles, a fob watch with a cracked face.

“We don’t get very many visitors,” said the girl. “My name is Constance. Where have you come from? Please, go on, sit there by the fire where it’s warm.”

Aurelia sat gingerly on a crooked bench. She held her satchel in her lap and pulled her feet close. “It’s a pleasure to meet you, Constance. I’ve come from London.”

“I’ve heard so much about London. My fiancé has told me. Will you have tea?”

“Only if it’s no trouble,” said Aurelia.

“Oh, it isn’t.” Constance was already reaching for a dented kettle. She moved stiffly, favoring her left side; her shoulder was hunched beneath a heavy shawl. “Gran would like some too, wouldn’t you?”

Constance smiled toward a dark corner of the hut. Eyes glittered in the shadows, and a mottled gray lump moved. Aurelia startled. She had mistaken the old woman for a pile of blankets.

“Aurelia has come to use the observatory, Gran,” Constance said. “Isn’t that grand? We don’t have many women come to our island.”

Aurelia twisted her gloves together on her lap. One of those rare women had been her mother, Letitia. Aurelia’s parents had stopped at Asunder Island long ago, before she was born. Their memories of soaring great Atrox had been among her favorite bedtime stories — although they had neglected to mention the grim village where wretched old women lived little better than animals.

“Gran likes visitors from far away,” Constance said.

Crouching in the corner, knees bent to her chest, the old woman said nothing. Beneath the folds of her skirt her toenails were yellow and curved. Gray hair fell in dirty hanks around her face. Beside her, in the corner, a wooden ladder jutted from a hole in the floor.

Gran blinked and Aurelia looked away, her face warm.

Constance set out chipped cups and saucers. The tea, she said, was a gift from her fiancé, a sailor at the whaling station on South Georgia Island.

“We’re going to be married soon,” she said.

“Does he visit often?” Aurelia asked.

“He was here last summer,” said Constance. “January, at the turn of the year. That was when we courted. He’ll return soon.”

“Will you go with him when you’re wed?” Aurelia asked, examining Constance with new interest. “Are you very excited?”

Constance knelt by the fire. The flames made her pale face look sickly and flushed. “Life aboard a whaleship is no place for a bride, is it?”

Aurelia’s vision of two young people sharing whispered plans for escape evaporated, and she felt pity so overwhelming she could almost taste it. The young man was likely oceans away by now, having forgotten all about the strange hunched girl waiting on a black lump of rock in the Southern Ocean, except perhaps when he needed a tale to share with friends. She thought I would marry her, he would say, and pass the bottle along. She smelled of fish and slept with rats and she thought we were in love, and he would laugh, he would light his pipe, he would speak of other things.

The kettle pinged and hissed. Constance wrapped her skirt around her good hand to lift it out of the fire. As she turned, her shawl slipped from her left shoulder.

The useless limb wasn’t an arm at all. It was a wing. The feathers were as black as oil.

Aurelia stared, her pulse thunderous in her ears. The captain’s warning, the sailors’ knowing laughter. The way Mr. Davies had shuddered with distaste and touched his handkerchief to the corner of his mouth when Aurelia asked about the inhabitants of Asunder Island and how they lived with the Atrox colony so near. She hadn’t listened. She hadn’t even understood what she was refusing to hear.

Constance tugged the shawl absently back into place and she was a girl again, only a girl, her deformity hidden. “Hot tea is the only thing for a day like this, don’t you think? Do you have wind like this in London? Here we are. I hope it’s strong enough.”

Aurelia drank without thinking. The tea tasted of moldy wood; she gagged and coughed. In the corner dark eyes sparked, and the old woman’s dry laughter filled the room.

“No,” said Aurelia, recovering. “We don’t have wind like this in London. Nothing like this at all.”

“Will you tell me?” Constance asked. When she spoke faint lines around her mouth creased; she was older than Aurelia had first thought. “We have so few visitors. I love to hear all about where they’ve come from.”

Aunt Theo would know what to say. She would overcome her shock at the existence of this chimerical girl, she would laugh away the awkwardness, she would fill the silence. But Theo had remained on the ship. Here there was only Aurelia with her unease and an afternoon to endure before dark. She sipped the foul tea and hoped Constance could not see how her hands trembled.

“What do you want to know?” she asked.

Constance’s expression was eager. “Everything.”

It was easier once she began to speak. It was only conversation, she told herself. It did not matter what Constance hid beneath her shawl. As the day waned she told Constance about London’s gardens in springtime, the rattle of carriages on paving stones, the markets and the pickpockets, church bells on Sunday morning. Constance was full of questions about the world beyond her island. Aurelia tried to explain how it felt to stand at the heart of London with the crowds pressing all around, so many people and so little space, the air so thick with the noise of them it felt like drowning, but all of her words were inadequate to span the distance between Asunder Island and home.

“It sounds remarkable,” Constance said, soft and wistful, pouring out the last of their second pot of tea.

“It is,” said Aurelia. She and Theo had left London months ago aboard a morning train to Southampton, and not until they passed the equator on their voyage south had Aurelia felt the pinch of homesickness in her gut and wished she had looked back for a last glance.

Her mother would laugh to hear them now. Letitia had always insisted London was dull and mundane, no comparison at all to the dark jungles and vast deserts and ancient cities of the world, all the places where a bold woman might go to feel joyous and alive.

Aurelia felt only cold and anxious. Her revulsion had softened, but she could not find enthusiasm in its place. Perhaps the joy came later, in the drawing rooms of less adventurous friends, where a crooked stone hut that stank of fish might transform into a bold Antarctic outpost, a lonely half-winged girl into an island princess.

“It will be dark soon,” Constance said. “Would you like to go to the observatory?”

The question caught Aurelia by surprise. The afternoon had slipped past in a dream of moldy tea and tiresome wind, and she felt breathlessly unprepared for the night. She fumbled for her satchel, dropped her gloves, mumbled her assent.

They went into the blustery dusk. Sunset burnished the sky in fiery shades, and faded, the last daylight leeching away. Bright stars emerged and Aurelia counted them one by one. Her neck ached. The wind was brutally cold but she lingered, watching the horizon, waiting. Years of planning, months of travel, and the tea had grown cold, and the earth had turned, and it was time. She had come so far to see —

There. The Summer Star was rising. A spark at the edge of the world.

From the chasm rose a sudden clattering roar. The Atrox were awake.

In the twilight Constance’s eyes had the same beetle-shell gleam as her grandmother’s. “They’re always restless at night.”

Inside, the observatory was surprisingly warm. There was a fire in an iron stove, and behind it, tucked in the corner, was the old woman.

Aurelia stopped short, but Constance didn’t notice. She bustled around the room lighting candles and lamps.

The old woman stared at Aurelia, unblinking. Here too she crouched beside a square hole where the arms of a wooden ladder reached from below. The noise of the Atrox was quieter inside, but the ground felt unsteady, as though the island itself were the flank of a great beast, rising and falling with slow breaths. Did those people who chose to — Aurelia glanced at Constance’s wing, cringed — intermingle with the Atrox stay below to live? Did they surrender to the caverns entirely? Aurelia strained to listen, but she could not hear human voices in that muffled roar.

“Do you know how to use the telescope?” Constance asked.

Aurelia pulled her gaze away from the old woman. “Yes, I do.”

“I don’t know much about it,” Constance admitted. “I used to play with it when I was little, but I could never see anything more than smudges of light. This here, this is how we open the roof.”

The observatory roof rattled as they turned the crank.

“It must be important, that little star,” Constance said. She wasn’t hiding her wing anymore. Hanging uselessly at her side, the long black feathers almost resembled fingers, or claws. “So many people come to look at it.”

“It is,” Aurelia said, “although not everyone agrees. Many astronomers say it’s only a curiosity.”

Before her journey began, Aurelia had received a dozen letters from concerned relatives and members of the Royal Society suggesting that while her capacity with sums was impressive for a woman, it would be better for her to devote herself to a more appropriate pursuit, such as a respectable marriage or a career as a governess, rather than spending so much ink pleading for an unnecessary Antarctic expedition. Think of Hugh and Letitia, they said. Would her parents not want better for her? After what happened to them, desiccated by disease beneath the pink stone palaces of Jaipur, surely they would want her to remain safe in London?

“But I think it’s far more than a curiosity.” Aurelia said. “You see, the Summer Star is moving.”

“All stars move,” Constance said.

Aurelia shook her head, warming to her explanation. “Not like this. It moves unlike stars around it. It moves with them too, rising and setting every day and through all the seasons, but it’s also moving between them. Not so we can see it with our eyes — we have to watch for years. But it’s still much faster than any star should move. Other stars have shifted only half a degree since the time of the Greeks, but this one, it’s crossed that span in less than a century.”

“Is it coming closer or going farther away?” Constance asked.

“I don’t know,” Aurelia said, an edge of frustration creeping into her voice. She was speaking too quickly, at a pitch too high. “There’s a man in England who suggests that all stars are moving away from the earth. But even for him, even with all of his equipment aimed at the very brightest stars, his flint prisms and his spectra — even then it’s a very difficult measurement. And the Summer Star is so unusual in its other motion, so strange…” Aurelia gestured helplessly. “I don’t know.”

“So much bother for one tiny speck of light,” Constance said, amused. “And there are so many stars.”

Aurelia stopped herself from making a sharp reply. Constance wasn’t being unkind. She didn’t care to hear about parallax and prisms, degrees and declinations. Aurelia turned her attention to adjusting the telescope. Soon the Summer Star’s nearest celestial neighbors would be high enough above the horizon for measurement.

“Do you need this? This is where the others have written down their numbers.” Constance carried a large leather-bound book to Aurelia, holding it against her body with her one hand. “You’ll have to write yours as well, won’t you?”

Aurelia took the book from her and laid it on her knees. She dug through her satchel to find her pen and ink. “Yes. Yes, of course. Thank you.”

The book’s pages were full of numbers, notes, and trigonometrical calculations spanning more than a century. A young stargazer aboard Captain Cook’s Resolution had been the first to measure the curious motion of the Summer Star, and a few years later his observations had captured the interest of Lord Petterdown’s father, who had spent an unseemly portion of his family’s fortune constructing the telescope on Asunder Island. New measurements had been added at odd intervals ever since, whenever a traveler or a sailor with a liking for astronomy made the journey.

Aurelia turned the pages carefully — the paper was dry and rotting at the edges — and stopped when her eyes found familiar handwriting. Her heart began to drum and her breath shortened. She traced the columns with her fingertips, catching on imperfections. She had known they would be in here. She had always known. But she had, somehow, expected her father’s handwriting, not her mother’s, not the elegant lines and curves of script she had coveted since she was a child, yearning for every new letter. At the top of the page were careless drops of ink and the smudge of a fingerprint.

“I remember them,” said Constance.

Aurelia resisted the urge to cover the book with her hands, to hide it jealously and clutch it to her chest.

“Do you?” she asked doubtfully. Her parents had visited Asunder Island before Aurelia was born, and she didn’t think Constance could be much older than her own thirty years. “You must have been very young.”

Constance sat beside her on the bench, brushing Aurelia’s shoulder. Where her arm should have been there was the unnatural give of feathers. Aurelia leaned away.

“They were a young couple,” Constance said. “Man and wife. I remember because so few women come here.”

Aurelia swallowed. Her mouth was dry.

“He was ill. He ought to have stayed on the ship. That’s what his wife kept saying,” Constance went on. “She made him rest on a pallet over there on the floor. They argued about it, but I think she was quite used to getting her own way. They didn’t seem to care much about the star, not the way you do. It was only a diversion to them.”

A storm of answers gathered on the tip of Aurelia’s tongue: But they were never ill, not until the end. They never argued. How could you possibly know what they cared about? They were alive and in love and this place, this grim little island, it was only a flicker in their lives. A breath, a blink, a bedtime story. They never told me about you.

“I confess I pitied her,” Constance said.

Aurelia closed her hand into a fist, creasing the edge of the paper. “What reason could you have for pity?” she asked, because she could not say: how dare you?

“She was unhappy.”

Aurelia had no memories of her mother being unhappy. Letitia was as radiant as a fairy queen, always in motion, pulling Aurelia’s laughing father in her wake. Aurelia could scarcely imagine how it must have changed at the end, when they were struck down by cholera. She had never forgiven them for dying so very far from her.

“Why do you say she was unhappy?” Aurelia asked.

“She told me a story to pass the time. Would you like to hear it?”

The answer thrummed in Aurelia’s fingers with her heartbeat. The numbers on the page blurred. She unclenched her hand and laid it flat, thumb covering the smudge of Letitia’s fingerprint. Everything she had learned, everything she had prepared, it all fled from her mind. There was only the wind rattling the roof, the woman beside her with an impossible wing, the restless Atrox, her mother’s ink beneath her hand. She had always thought her mother had such delicate hands, but she had been a child, and a child’s memories were less trustworthy than the sea before a storm.

“I have quite a lot to do,” Aurelia said.

It was the coward’s response.

“This woman,” Constance began, “she said — “

“Letitia,” Aurelia said. “Her name was Letitia.”

Constance looked at her with something like pity. “I thought you had the look of her.”

Aurelia set the book aside. Her breath hitched, and she was a child again, watching through the parlor window for the carriage that would bring her parents home, excited and terrified and hungry for a glimpse of their faces, for the music of their laughter.

She said, “I would very much like to hear the story she told you.”

They had been sailing between England and the Australian colonies, adventurers flying across the world, never allowing the snares of society to catch their heels. Letitia was the only woman aboard, but the crew gave her little trouble. She was a gentlewoman, and her husband was strong and blessed with an Irish temper.

(Aurelia smiled, remembering her father’s red face and untrimmed whiskers, the boom of his voice, the songs he taught her to shock disapproving nursemaids. They could have been great friends, father and daughter, if only he had quelled his wanderlust, or lived long enough to take her along.)

One night during this journey Letitia woke from a restless sleep to find the ship still in the water. Desperate for a breath of fresh air, she slipped from her husband’s embrace and fled their stuffy cabin. On deck the sailors had fallen asleep at their watch; not one stirred at her approach. It should have worried her, but she felt only relief to have the night to herself.
There was no moon, but the starlight on the sea was bright enough for her to see an island nearby: a gentle hump of land, a necklace of silver sand, a dark thatch of palms.

The night air was cool and pleasant on her skin. She gulped it in greedily, tasting each breath. Though she was newly wed and very much in love, Letitia still harbored the suspicion that the farther she ran, the smaller the world became, the more insidious its traps. London had grown too close for her, England as well, and every grand city in Europe. She had thought to escape by setting sail, but even the world’s oceans seemed to be shrinking around her, the horizons creeping closer with every day. She knew in the morning her restlessness would fade, and she would walk the deck on her husband’s arm, and they would talk of the places they would go, the wonders they would see. You are so very lucky, her mother had said when she married, the needles in her voice belying the kindness of the words. You are so very lucky to have found a man to indulge your whims, to keep you safe from your wildest impulses.

But now Letitia stood with no one but the sea. She could not bear to return to the suffocating cabin and the scratch of her husband’s chest against her cheek. The night was as untethered as a dream. It had been too long since she let a wild impulse take her.

She stepped out of her nightgown, climbed onto the wooden rail, and dove into the water. She swam toward the island with long, smooth strokes. She did not stop until she felt the sugar-soft sand beneath her feet.

When she emerged from the sea, the women were waiting.

They stood like sentries on the beach, unsmiling in the starlight. They were dark and pale, sturdy and thin, young and old. Letitia wrung seawater from her hair and did not let herself tremble under the weight of their stares.

The line of women parted, and an old woman appeared. She was hunched and round with plaited gray hair hanging over her shoulders. She held out a hand and led Letitia up the beach to where a great bonfire raged.

Around the fire the women danced and sang into the night. Letitia did not know their languages, for they spoke dozens, but she understood every song. They told stories of escaping their own husbands and mothers and the pretty cages their families had built for them, how they crafted boats and wove sails and chased the wind across storms and sunrises. Each woman’s voice lifted in an exultant shout, and she threw her arms to the sky, and her arms became wings, and she rose on the cries and cheers of the others.

(In the eyepiece of the telescope, the Summer Star wavered, blurred. Aurelia remembered sitting quiet as a ghost in her mother’s room, watching Letitia dress for a party, and the thin twin scars she spied between Letitia’s shoulders. She had invented her own stories for her mother’s old wound: a jaguar stalking through the jungle, a headhunter in the Amazon, a sultan’s flashing sword in an Arabian desert. Had she imagined a pair of wings unfurled? What a fanciful child she had been.)

The night lasted years. Letitia danced until her skin wrinkled and her breasts sagged, her voice cracked like old wood and her hair grew matted and gray. She forgot her own name, her husband’s touch, her mother’s voice, the cool green homeland she had left behind. She danced to welcome every new woman who surged ashore.

Then it was her turn to stoop and shuffle as the younger women stepped aside, to hold out a welcoming hand to a girl who emerged dripping and wary from the waves.

But when Letitia caught the girl’s hand, smoke and saltwater cleared from her eyes. The girl had Hugh’s red hair, Theo’s Roman nose, Mother’s pinched scowl. The sky to the east was brightening. The dark silhouette of a ship marred the water.

Letitia gripped the girl’s hand and pulled her into the waves. Fear was a fire in her throat. They dove together, and with every stroke the years washed from Letitia’s body. When she reached the ship and scrambled up the ropes, her hair was dark again, her skin smooth, her limbs straight and strong. Her nightgown lay where she had left it. She dressed with shaking hands.

She looked back, but the island was gone. There was only a burst of seabirds, specks of shadow in a gray dawn, whirling and rising as the sun swallowed them.

It wasn’t until she was settled again at her husband’s side that she remembered the girl. She pressed her fingers to her lips to muffle her sobs. They had been swimming together, then she was alone, and she had not felt the moment the girl slipped away.

“That’s all she told me,” said Constance. “The island was gone. The sailors had never seen it. She was your mother?”

Aurelia scrubbed at her damp cheeks and cleared her throat. “Yes. She — yes. She used to tell me stories of her adventures. She was… They were always sailing away to somewhere new, some faraway place. Every time they sent a letter I would find them on a map.”

Aurelia had been twelve years old when a letter brought the news of her parents’ deaths to Aunt Theo’s house in London. Old enough to read it for herself, young enough to declare it a lie. She was adamant: there was no way they could know for certain what had happened. They had no proof. For two months she presented her hypothesis every morning over breakfast. India was very far away, and who was this army officer sending them letters anyway? Her mother and father had never contracted cholera here, in London, and why should Indian cholera be so very different? Had they not survived ordeals far stranger? The next letter — this was the culmination of Aurelia’s thesis, punctuated with the clatter of a spoon on china — the next letter would arrive any day now, and that stranger would be shown for the fool he was. What a mistake I have made, he would say. It was another girl’s parents who perished. Yours have already set sail for home. They will be with you soon. What a terrible mistake I have made.

Aurelia remembered how Aunt Theo had listened with tears in her eyes, tears Aurelia scorned because there was no reason to cry. She remembered finding Jaipur on a map of the world and tracing the long route back to London: overland to Bombay, aboard a ship around the Cape of Good Hope, north across the doldrums, riding the westerlies home. She remembered the feel of the map beneath her fingertip, the clean lines made imperfect when ink smudged from her touch.

What she couldn’t remember was when she had stopped imagining her parents as a speck on a map coming ever closer, and when she had begun instead to see them as shades retreating into the distance, all color and light and laughter washed away, echoes of echoes fading to silence.

“She never told me that story,” Aurelia said, envy sour at the back of her throat.

Constance’s face fell. “I’m so sorry. I’ve always remembered her.”

Aurelia’s jealousy vanished as quickly as it had sparked, and in its place she felt only sadness. Sadness for Constance on her lonely island, collecting the stories of strangers, forever trapped between the two worlds to which she could never fully belong. For the restless young woman Letitia had been, sitting on this same bench, beneath the dome of this same telescope, sharing a small secret piece of her heart. For the little girl who had traced her fingers over maps and watched at rain-streaked windows for a carriage that never came.

“I could tell you more,” Aurelia said, “if you like. My mother had so many adventures, and even a short night can feel very long.”

Through the night they shared stories as Aurelia measured the stars. Aurelia spoke of her parents and eventually herself, her voyage south and how long she had yearned for it, and Constance told her about all the people who came to Asunder Island to study the stars or the Atrox, from those who stayed only a night to the others who went into the chasm and never returned. Aurelia could not bring herself to ask if there was a woman below with Constance’s pale face and freckles, human in form but birdlike in manner, thinking only sometimes about the hybrid daughter who lived above. Her curiosity was fierce, but it was not more important than allowing Constance the dignity of deciding what parts of herself to share.

Accompanying their voices was the ceaseless wind, the restless birds, the soft scratch of Aurelia’s pen. With every memory and every measurement she felt something untangle in her chest. The Summer Star had four close companions in the night sky, and she recorded the distance between each pair carefully, once in the book, again in her own journal. So much fuss for such a little speck of light, but for that night, in that place, the star was hers.

She made notes as new ideas occurred to her, planning the first of what she was sure would be many letters to the Royal Society. It was time to learn about spectra and prisms and the optics of starlight falling on earth, if she wanted to discover which direction the Summer Star was traveling. There was no reason to wait for somebody else to solve the problem for her.

Eventually dawn chased away the polar night and the stars faded. Constance had been quiet for some time; Aurelia had not noticed when their conversation faltered. She made a final note in her journal, rolled her tired shoulders and rubbed her eyes.

Her movement broke the quiet that had settled over the observatory. The old woman, still as a statue for hours, blurred into motion. Her legs unbent, her arms flashed. Aurelia saw yellow teeth, the red cave of her mouth, and before she could even catch a breath the old woman was gone, scurrying down the ladder like a spider on a web.

“She worries about them before they fly,” Constance said. “She likes to see them off.”

Her voice was mild, but Aurelia felt the words as a reprimand. She had scarcely been able to glance at the old woman, too afraid of staring, too absorbed in her own disgust. Had she looked closer she might have seen the concerned grandmother beneath the grime, the one for whom the colony below and the island above were only different rooms in the same house.

Constance banked the fire and doused the lamps. Aurelia blew on the book to dry the last of her ink. They closed the observatory dome and went into the cold, cold morning.

The Atrox were even louder outside. Aurelia stepped toward the chasm, but Constance stopped her with a hand on her arm. They stood shoulder to shoulder, backs to the sunrise, rocked by the wind. The sky was a painter’s canvas of pink and gray and orange, brush strokes untamed and beautiful.

Beyond the black shoulder of the island, beyond the chasm and the smoke and the gray waking sea, the Summer Star lowered itself toward the horizon. The sun rose, and Aurelia’s shadow stretched beside Constance’s, long inseparable spindles reaching to the crevice. A heartbeat, a held breath —

The Atrox took flight.

They exploded from the chasm in a fury of thunder and black wings. The gust knocked Aurelia backwards — hot, scented of sulfur and fire. The noise was deafening. The birds whirled in a long spiral, blanketing the island in shadow. The sky was a shroud of wings and reptilian yellow eyes. Claws, curled. Heads angled toward the sky.

Aurelia’s heart was racing. She began to shiver. She felt impossibly light, freed from gravity. All she had to do was raise her arms and she would soar as well.

The cloud of birds lifted and dawn returned, and with it the shimmering sea. The last Atrox beat their way out of the chasm to follow the black cloud to the west, to their star, the Summer Star, their noise and their stench fading as they raced away. The flock became a puff of coal smoke, a thread of black silk, and the sky swallowed it in a flash of impossible starlight. The birds were gone. The Summer Star had set.

“They’re lovely, aren’t they?” said Constance softly.

Aurelia had no answer. Weight returned to her limbs, pressed her feet to the ground. She hesitated too long, pulled herself back to earth too slowly, and Constance was turning toward the stone cottage.

“Wait,” Aurelia called.

Constance stopped.

“You can come with me.”

Constance tilted her head, an unnervingly birdlike motion. “Come with you?”

“To England. To London. You don’t have to stay here. Come with me.”

In the dawn light the faint lines on Constance’s face stood out as shadows. “You’re very kind,” she said. She tugged her shawl over shoulder, hiding the wing that would never carry her to the sky. “It was so lovely visiting with you, but you had best hurry to the beach. The sea is rough today. They’ll be wanting to take you away soon.”

She disappeared into the hut.

Aurelia looked at the closed door for a long moment, seized by indecision. She could run after her, pound on the planks, convince Constance of her sincerity. Prove the disgust and pity she had felt was gone — but it was a selfish impulse. Constance was not a child, however young she looked. She did not need Aurelia’s approval, nor her rescue. Aurelia turned her back to the village in a confusion of disappointment and relief, sensations unmoored by the morning wind.

The trail to the beach was littered with black feathers. Aurelia collected a handful and tucked them into her satchel. They were unexpectedly sharp, pricking her skin like nettles. Mr. Davies had neglected to describe the physical properties of the feathers in his monograph. She would have to write her own account — her interaction with the Atrox was limited, to be sure, but she could at least mention the feathers.

She had scarcely considered what might come after her journey’s purpose was fulfilled. She had been following the footsteps of others, looking to affirm what they had already discovered. She could not remember why she had ever thought challenging Lord Petterdown would have been enough. He was only a man, a diversion in a world of wonders. There were truths yet to discover about that odd outcast star that sat so uneasily in the night sky, questions pressing at the back of her throat. Asunder Island sat alone at the end of the world, but an end was not so very different from a beginning.

But that was for tomorrow. Today she would return to the ship, and Aunt Theo would check her calculations and chuckle in her deep alto voice, and she would propose a toast: to proving the men of the Royal Society wrong, to humiliating Lord Petterdown, to unladylike curiosity and scientific inquiry, to questions with answers waiting to be found. To the excitement of traveling the world and the comfort of returning home. They would drink the cognac Theo had been reserving for this occasion, and they would drink more, and as the warm sleepy flush spread, Aurelia would tell Theo about Constance and Letitia’s lost island in the South Pacific. Theo’s eyes would soften with surprise, and it wouldn’t be as difficult as Aurelia had always imagined it to be, to allow Letitia to shine again for moments between them, as infuriating and impossible as she had been in life.

And they would toast again, Aurelia to her mother, Theo to her sister, to the life she had lived in the only way she knew how, to sailing their own oceans to do the same. They would toast to one journey ending and another beginning, and because Letitia would have laughed they would laugh as well, their voices small in the heart of the sea.

Clouds crawled across the sky. The ocean was choppy and flecked with white. Aurelia picked her way down the steep slope to the beach. She drew her scarf over her nose and watched the dinghy appear as a black speck in the distance.

Kali Wallace studied geophysics before she realized she enjoyed inventing imaginary worlds more than she liked researching the real one. Her short fiction has appeared in Clarkesworld, F&SF, Asimov’s, Lightspeed, and Tor.com. Her first novel will be published by Katherine Tegen Books/HarperCollins in 2016. She lives in southern California.