The Sins of Our Fathers

An Expanse Novella


By James S. A. Corey

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The final novella set in the universe of James S. A. Corey's NYT-bestselling Expanse series. Now a Prime Original series. This story is also available in the complete Expanse story collection, Memory’s Legion


Through one of the gates, a colony stands alone. Their supplies are low. Their defenses, weak. The leadership is uncertain, and the community fragile. Huge alien beasts threaten the little they have left.
But the worst monsters are human, and the greatest dangers are the past they brought.
The Expanse
Leviathan Wakes
Caliban's War
Abaddon's Gate
Cibola Burn
Nemesis Games
Babylon's Ashes
Persepolis Rising
Tiamat's Wrath
​Leviathan Falls

Memory's Legion

The Expanse Short Fiction
The Butcher of Anderson Station

Gods of Risk
The Churn
The Vital Abyss
Strange Dogs
The Sins of Our Fathers


The Sins of Our Fathers

The monsters came at night.

First came their calls: distant and eerie. Their wide, fluting voices echoed down the valley, complicated as a symphony and mindless as a cricket swarm. The deepest of them sang in a range below human hearing: subsonic tremors that the people in the township felt more than heard.

Then the night scopes showed movement. It could start as far as twenty klicks away, or as near as two. The science team still hadn’t figured out what they did during the daylight hours or during the long, empty days when they seemed to disappear, but the feeling that they rose up from the planet’s flesh with the darkness made the approach feel almost supernatural. Like the town had offended some nameless local god by coming here. It was only a mystery, though. They’d figure it out eventually. If they survived.

After the movement, assuming the monsters kept to their same pattern, their chorus would go on until the little retrograde moon started rising in the west. Then it would stop. Then they would come.

“They’ll aim for the breach,” Leward said, pointing with his chin. The perimeter wall was constructed out of prefabricated plates of carbon-silicate lace scavenged from ship hulls. The braces were titanium and compression-resistant ceramic. The place where the monster had come through last time looked like God had come down and pressed against the wall with His thumb. Ten meters of shattered plate and bent brace they’d shored up with local trees and scrap.

“Might aim for the breach, might not,” Jandro said, with a slow shrug. He was the head of construction and maintenance, and a bear of a man. “What you think, Nagata?”

Filip shrugged. His mouth was dry, but he tried to keep the fear out of his voice. “Wall didn’t slow them down much even when it was intact.”

Jandro grinned and Leward scowled.

The town was the second largest on the planet Jannah, at four hundred and thirty-six people. It had been named Emerling-Voss Permanent Settlement Beta, but everyone called it Beta. And with the ring gate to anywhere else broken, that meant Beta was its name from now on. Without the gates, the corporate headquarters of Emerling-Voss was just shy of twenty-three light-years away. Alpha settlement, with more than a thousand people, was seven and a half thousand klicks to the south. With no orbital shuttles or reliable ground vehicles, it might as well be seven million. And Alpha had gone silent when the ring gates shut down. Whether it was just a radio malfunction or something larger was an open question, and the residents of Beta had more immediate problems.

There were two dozen people drawn from different workgroups all along the north wall. Leward was in charge there. Another group was along the east, with lookouts and runners at the west and south in case something unexpected happened. In case the monsters changed the direction they’d traveled up to now. Filip considered the faces of the others stationed below the wall, finding signs in each of them of the same fear he felt. Almost each of them. Jandro and the four men from the maintenance team seemed relaxed and at ease. Filip wondered what drugs they’d taken.

Leward hefted his torch: a titanium rod with a solid, waxy mat of the local mosslike organism on a spike at one end. When he spoke, it was loud enough for everyone to hear. “When they come—if they come—we deflect them. Don’t go at them straight on. Just turn them gently aside so they don’t get to the walls. We aren’t fighting them. We’re just herding.” He nodded while he said it, like he was agreeing with himself. It made him seem uncertain.

“Should just shoot them,” Jandro said. It was a joke. Everyone knew the town had run out of rifle cartridges and the reagents they’d need to print fresh ones.

“We keep them outside the walls,” Leward said. “But if they get in anyway? Get out of the way.” He pointed up and to the south at the fabrication lab, the only two-story building in Beta. “The engineering team has a magnetic slug thrower set up. We don’t get between it and the target.”

“Maybe they won’t even come this time,” one of the others said. As if in answer, the uncanny chorus swelled. The overtones rang through each other like a ship drive finding a hull’s harmonic. Filip shifted his weight from foot to foot and hefted his torch. Everything was too heavy here. He’d spent most of his life on ships, and the float or one third g were his natural state. When he accepted the job to join Mose and Diecisiete at Beta, he’d expected three years down the well at most. Now, it looked more like a lifetime. And a lifetime that might not last until dawn.

Leward’s hand terminal chimed, and the team lead accepted the connection. Evelyn Albert’s voice came loud enough that Filip could make out every word. “Get your people in place. We have movement half a klick out. North by northeast.”

“Understood,” Leward said, and dropped the connection. He stared out at all of them like an actor who’d just forgotten the St. Crispin’s Day speech. “Get ready.”

They moved toward the wall, and then through the access gate to the strip of cleared land outside it. The night sky was bright with stars and the wide disk of the Milky Way. With the autumn sun gone behind the horizon, the air cooled quickly, with a scent like mint and toilet cleanser. The atmosphere of Jannah smelled nothing like Earth, the Earthers at Beta said. Take away the mint, and Filip thought it smelled a bit like a freshly scrubbed ship.

None of that changed the fact that Filip and the torch bearers walking at his side were the invaders here, and he’d have argued for leaving again if there were a ship that could take them and anyplace to go. Instead, the walls, the darkness, and the rising howls of monsters outside.

He tried to hear a difference in the chorus. He imagined the huge beasts hauling themselves up out of the dark soil like the ancient dead coming up from their graves. It seemed like the kind of thing that would have to change how they sang, but he couldn’t be sure. He took his place outside the wall. To his right, a couple of women from the medical team. To his left, a young man named Kofi with the long bones and just-too-large head that said he was another Belter like Filip.

“Hell of a thing,” Kofi said.

“Hell of a thing,” Filip agreed.

In the west, a dim light glowed at the top of the mountain ridge like a pale fire was burning there. It brightened, and resolved into a crescent, smaller than Filip’s thumbnail. It looked to him like inverted horns.

All through the wide valley, the choir of alien voices stopped. Filip felt his heart start to labor. His head swam a little. The sudden silence made the valley feel as vast as space, but darker. The fear crept up the back of Filip’s throat, and his hands gripping the torch ached.

“Steady,” he said under his breath. “Steady, coyo. Bist bien. Bist alles bien.” But it wasn’t true. Everything was profoundly not fine. Leward paced behind them, breath fluttering like the edge of panic. Then from the darkness, a steady, heavy tramping that grew louder.

“Time to dance,” Jandro said. A flare of orange fire sprang up to Filip’s right. Jandro holding his lit torch.

“Not yet, not yet,” Leward said, but Jandro’s team had already started lighting all of their torches, and the approaching footsteps were so loud, Filip had to agree. The others along the line set fire to the moss, and Filip did too. The Belter beside him was struggling with the igniter, so Filip leaned his own fire close until the flames spread. The cleared space was a bright monochrome orange. Smoke stung Filip’s eyes and throat.

The first of them loomed up out of the darkness.

It stood higher than a building, at least any of the buildings on Beta. It moved with weirdly articulated shoulders and hips that seemed to ripple with every step like there was a vastly complicated mechanism under the rough skin. Its head was little more than a knob, set low between its shoulders, comically flat. The eyes were black: two at the front and two on the sides, and its mouth curved up like an obscene, toothless grin. It lumbered forward, into the light, seeming not to notice the line of flame and primates in front of it.

“Not straight on!” Leward shouted. “Turn it! Make it turn!”

The line to Filip’s right surged forward, shouting and waving their torches. To his left, they hung back. In the center, he could go either way. The monster took a slow step, then paused as Jandro and his crew rushed at it from the side screaming obscenities and threats. The monster’s grin seemed to widen, and it trudged forward, the ground shaking under each step. Filip lifted his own torch and rushed in. The monster’s smile was an accident of its physiology and evolution, but it still felt like the great beast was pleased to see them. Or amused. Filip pressed himself in among the men, shouting and reaching up to thrust fire at the thing’s dark eyes.

The monster made a deep fluting groan, and its next step angled away to the right, if only a little bit. A few degrees.

“Hold the line!” Leward shouted over the roar of the torch bearers. Over Filip’s own shout of victory. “It’s not over. Keep turning it!”


  • "Corey deftly weaves multiple points of view to create a dense and colorful tapestry of political intrigue, personal relationships, and sophisticated technology that bursts with action but also delivers an introspective view of the characters as they age and reflect on their purpose and the value of their lives."—Booklist (starred review) on Tiamat's Wrath
  • "A standout tale of violence, intrigue, ambition, and hope. ... Corey cranks up the tension relentlessly in this fast-paced story of heroes and rebels fighting for freedom. With enough thrills and intrigue for three Hollywood blockbusters, the novel stands alone nicely, making it easy for new readers as well as diehard series fans to dive right in."
    Publishers Weekly on Nemesis Games
  • "The science fictional equivalent of A Song of Ice and Fire...only with fewer beheadings and way more spaceships."
    NPR Books on Cibola Burn
  • "Combining an exploration of real human frailties with big SF ideas and exciting thriller action, Corey cements the series as must-read space opera."
    Library Journal (starred review) on Cibola Burn
  • "The Expanse series is the best space opera series running at full tilt right now, and Cibola Burn continues that streak of excellence."
    io9 on Cibola Burn
  • "Corey's splendid fourth Expanse novel blends adventure with uncommon decency."
    Publishers Weekly (starred review) on Cibola Burn
  • "A politically complex and pulse-pounding page-turner.... Corey perfectly balances character development with action... series fans will find this installment the best yet."
    Publishers Weekly on Abaddon's Gate
  • "It's been too long since we've had a really kickass space opera. Leviathan Wakes is interplanetary adventure the way it ought to be written, the kind of SF that made me fall in love with the genre way back when, seasoned with a dollop of horror and a dash of noir. Jimmy Corey writes with the energy of a brash newcomer and the polish of a seasoned pro. So where's the second book?"
    George R. R. Martin on Leviathan Wakes
  • "An excellent space operatic debut in the grand tradition of Peter F. Hamilton."
    Charles Stross on Leviathan Wakes
  • "High adventure equaling the best space opera has to offer, cutting-edge technology, and a group of unforgettable characters bring the third installment of Corey's epic space drama (after Caliban's War and Leviathan Wakes) to an action-filled close while leaving room for more stories to unfold. Perhaps one of the best tales the genre has yet to produce, this superb collaboration between fantasy authors Daniel Abraham and Ty Franck should reawaken an interest in old-fashioned storytelling and cinematic pacing. Highly recommended."
    Library Journal (starred review) on Abaddon's Gate
  • "Literary space opera at its absolute best."
    io9 on Abaddon's Gate
  • "[T]he authors are superb with the exciting bits: Shipboard coups and battles are a thrill to follow."
    Washington Post on Abaddon's Gate
  • "Riveting interplanetary thriller."—Publishers Weekly on Leviathan Wakes

On Sale
Mar 15, 2022
Page Count
64 pages

James S. A. Corey

About the Author

James S. A. Corey is the pen name of Daniel Abraham and Ty Franck. In addition to writing the novels and short stories of The Expanse, they wrote and produced the television series of the same name. Daniel lives with his family in the American southwest. Ty will tell you where he lives when and if he wants you to come over.

Learn more about this author