Exo by Colin Brush (EXCERPT)

Hello, dear readers! Today, we have a thrilling excerpt for you from a debut novel that expertly melds a future Earth devastated by climate change with a compelling murder mystery, featuring an octogenarian sleuth.

Our heroine Mae Jameson is no Miss Marple tho. Thirty years ago, she returned to a hostile Earth, determined to find a former lover. Now she ekes out a living on a planet that has turned against humanity, its oceans having turned into an annihilating liquid entity known as The Caul. Every living creature approaching its shores is irresistibly compelled to enter. . . and is never seen again. Scientists, some of the few inhabitants left, work in facilities seeking to understand and stop the Caul, and perhaps pave the way for humanity’s return from the orbital habitats and moon colonies where they presently live in exile.

Carl Magellan is a rogue scientist whose obsession with The Caul outstrips what others might consider both sense and decency. When Mae discovers his notes on the origins of the killer oceans, she’s plunged deep into the heart of a dangerous conspiracy. Someone believes that they can use the secret of the Caul to shape humanity’s future, and they aren’t afraid to kill to keep control of it.

Read on for a glimpse into Mae’s life, as her past and present collide before plunging her into a mystery perhaps only she is uniquely equipped to solve!

~~~~~~~

DAY ONE

Mae was out checking her traps when she found the girl.

It had been a long, disappointing day. Most of the cages were empty. After consulting her map—three traps left before she was done, each a long walk, close to the Caul—she’d trudged reluctantly towards the shore. Her pack, a couple of meagre marbit carcasses hanging from it, felt heavy. Pebbles rolled under her moccasins, jarring her brittle bones. If you weren’t careful, you could turn an ankle. Once, she’d always been in a hurry, careless of how the stones shifted under her feet. Now she didn’t give them the chance. Besides, what need had she for hurry?

The persistent wind—some days it blew until your head hurt—gnawed her ears and needled the craggy contours of her face. Another winter on its way. Her thirtieth here. But who was counting? Who wanted to be reminded they were an exile, a prisoner, a ghost? She’d come here to find somebody and turned into a nobody.

Here and there, wiry sparsely-leafed bushes grew. Brittle and dry, they survived on frugal falls of rain. Numbers were thinned through uprooting by storms which spilled out of the Caul and by her fellow penitents’ kindling-gathering. She stepped over a grey-brown vine growing in a straight line. Its hard, succulent tear-shaped leaves, if eaten, would make you sick for days. These creepers grew in one direction: towards the grey mass to the south.

The distant booming on the shore was like hammer blows on stone. She passed a rusted hulk sinking into the plain. An exterior door hung open, steps descending into the pebble grave in which the rocket’s nose was buried. Wind whistled through gaping plexiglass-scavenged portholes. Networks of alloy pipes clung to the hull like cobwebs. Ribbed burners pointed at the sky like giant clapperless bells.

The first two traps were empty, the second’s bait was gone. She scraped away the rust speckling the tripwire with her knife. She popped open a small plastic vial and applied grease sparingly, wishing she could do the same to her own joints. She replaced the lost bait with a succulent green leaf.

She looked up. Had she heard something? In the distance was another wreck. A brown pipe on the horizon. The feeling of being watched was strong. She shook her head. You had to guard against it. The Caul had you imagining all sorts of things. She sniffed the air: dust, time-pounded stone. For others it was metal, plastics, recycled air—the stale reminders of confinement. Hers was the quarried walls of the Mars orphanage and the church’s chill benediction. She hated the smell of dust.

The trap was set. Last one and then home.

The rusting hulk was long and thin. It had come down close to the Caul and years of storms had wrought brutal devastation: broken-backed, skin-pitted, holed. She gave the rocket a wide berth.

Hairs rose on the back of her neck. That uneasy feeling of not being as alone as you had thought. She still trusted her senses. Some of her fellow penitents called that a weakness. But in her former profession it had been her strength. Watching, listening, sniffing out evidence. Of course, none of it had helped here. Ghosts left no traces.

Pausing, she peered closer at the ship’s carcass.

Out of a dark hole in its base a white face stared back at her.

Small, rosy-cheeked. Round, almost boyish, features that despite their paleness reminded Mae of someone. The same someone who’d damned her to this planet.

Neither of them moved for a time.

The face disappeared and a short while later a little girl emerged from behind the ship. She wore a red coat and red boots. The coat toggles were undone. Under the coat was an odd, ankle-length green dress with buttons down the front from collar to hem. The girl had long, straggly, chestnut hair and about her mouth and grey eyes there was a cool blankness. She stood stiffly, arms at her sides, as if chilled. She didn’t move, only stared. She appeared to be six- or even seven-years-old, but Mae knew she was younger.

Mae looked around but could see no sign of Magellan, her father. Where was he? The man knew enough not to allow his daughter to stray like this. She bit her lip. And Mae knew enough not to mix herself up in the affairs of other penitents.

She broke eye contact with the girl and continued walking.

After a hundred metres she turned and saw that the girl—her name was Siofra—was following, stumbling over the pebbles. When Mae stopped, so did the girl. They regarded one another for a short time. The girl looked miserable, weary. Mae wanted to shout Go back to your father, but didn’t trust her voice. They barely knew each other. The child wasn’t her responsibility. Siofra had to be made to understand that.

Mae carried on and this time she didn’t stop to look back.

*

It wasn’t long after she started back that Mae realised she was going to have to take some sort of direct action to stop the child following her home. “You go the other way. Back to your father.”

This and other suggestions were greeted with wide blank eyes and pouting mouth. Mae took to throwing stones, but because she was afraid of actually hitting the child, her shots were unconvincingly short or wide.

“Are you lost? It’s that way.” She pointed back the way they had come.

Half an hour of this and Mae’s patience ran out. She turned and walked up to the child. “What do you want?” she shouted. The girl didn’t even flinch, just looked up at her. Mae put her hands on Siofra’s shoulders and turned her around, gave her a gentle shove. Siofra took two steps and stopped. She turned and faced Mae. Her grey eyes were cold. She held out the folded piece of paper. Mae swore silently, took it and opened it out.

She saw a crude drawing of a tree, done in pencil, and a string of numbers, in pen. A gust of wind nearly ripped it from her hand. “What’s this?” she asked, disgusted. She hated being manipulated.

The girl ignored her.

Mae clutched the paper tight. Was it a message from Magellan? Or did it mean something to the girl? I don’t want this, she thought, but for good or ill it was now hers and could not be dismissed.

“Shit,” breathed Mae, shaking her head.

It was the wrong direction. It would be dark in under two hours, it would take two just to return here and two more to get home. Perhaps she could talk Magellan into giving her a ride. He’d owe her for this.

It was over three kilos to Magellan’s place. She walked ahead, Siofra a few metres behind. The girl seemed reluctant now, lagging back. Perhaps there’d been a row and the girl was in the doghouse. Maybe she’d even run away.

So what was the paper for?

The girl and her father had always seemed close. Unlike so many strained relationships beside the Caul, there appeared to be a silent understanding between the pair. Might something have happened then? “You and your pa fallen out?” she asked.

The girl didn’t respond.

“Running away doesn’t fix anything,” she said. She could hear the Caul booming across the shore. “Just puts at least one of you in a very bad place.”

This was her bad place. Purgatory, hell. Call it what you like, Mae was being punished. Punished for having a heart, punished for daring to love someone and not being able to let them go. She looked at the girl, telling herself this was simply a head problem. Straightforward resolution, minimum involvement.

The clouds darkened as the light drained from the sky.

“How old are you?”

Siofra held up four fingers fully and one partially. She smiled.

Mae looked at her. “Well, Siofra Magellan, who is four and a half, this is the longest conversation I’ve had in months. Even if it is entirely one-sided.”

Siofra’s eyes returned to their vacant state.

They continued in silence, walking alongside the ridge pushed up by the Caul. Mae liked to keep the grey out of sight, if she could help it. They passed a few gnarled, twisted, deep-rooted bushes. Dead, killed by the slow toxicity of the encroaching Caul. She felt the shifting mass in the pebbles under her feet, the tug of it.

Control in all things. That was the secret. Over the years she had learned to devote her full attention to every action. But there was still that familiar tingling—a sense of being watched—when her back was to it.

She noticed Siofra’s gaze kept returning to the dead animals hung from her pack.

The girl’s eyes narrowed, got a curious look. “Do you like marbit?”

Siofra’s mouth twisted in distaste.

Mae smiled. “We have to make do with what we can find. Of course, you and your father don’t do so badly.”

At mention of her father, the girl’s face fell. Mae said nothing more.

~~~~~~~

From Exo by Colin Brush. Copyright © 2025 by the author and reprinted by permission.

Exo by Colin Brush was published today November 18 2025 by Diversion Books and is available from all good booksellers, including