Maryrose Cuskelly's The Cane based on the disappearance of Marilyn Wallman 50 years ago

Her younger brothers were 10 minutes behind her, but when they got there, they found her bicycle by the side of the road, the contents of her school bag strewn across the road.

Marilyn was nowhere to be found.

Fifty years later, the case is one of Queensland's oldest cold cases. In 1974, a bone fragment was found 40km away from her last known location. In 2015, the Queensland coroner confirmed it belonged to Marilyn.

To this day, no one has been charged in connection with her disappearance, and in March, her family called for a $1 million reward in a final bid to find out what happened to their daughter and sister.

Two years previously, seven and five-year-old sisters Judith and Susan Mackay were taken from a school bus stop in Townsville, raped and murdered, their bodies found three days later in a dry creek bed 40km away.

Maryrose Cuskelly recalls both cases from her childhood. Growing up on a farm outside Toowoomba in the state's south-east, she remembers the sense of unease and fear that gripped Queensland at the time.

"Suddenly the parents in our district were organising carpools to get us all to school - we were farm kids, used to a free and easy childhood, used to walking to school," she says.

"We'd all pile in the back of someone's ute and head off to school. We were probably in more danger of being thrown off the back of the ute than being abducted, but that's not how fear works. Fear works in a very particular way."

Cuskelly used to write non-fiction. Her 2008 work The End of Charity: Time for social enterprise (with Nic Frances) won the Iremonger Award; in 2010 she wrote Original Skin: Exploring the marvels of the human hide.

But the Wallman case was always in the back of her mind.

Her 2016 essay Well Before Dark, which examined Marilyn's disappearance, won the New England Thunderbolt Prize for Crime Writing (non-fiction), and it reignited a flame.

"I had always considered myself a non-fiction writer, and when I contemplated writing fiction, it just seemed too hard, really," she says.

"You have to kind of make all that stuff up, create these seamless worlds.

"I had considered writing about Marilyn as a full-length, non-fiction book, to expand on the essay, but the more I thought about it, I realised I could write more freely about some of the ideas I was interested in if I turned to fiction."

The result is The Cane. Sixteen-year-old Janet McClymont has gone missing from her hometown of Quala in north Queensland's cane country.

She was on her way to babysit at the neighbouring farm, and only her bag has been found. Was she kidnapped, was she murdered, or did she simply run away to Brisbane?

Weeks on, there's been no sight of her, and a sense of dread and distrust permeates the small town. Children dream of a presence in the cane fields, the farmers want to get on with the harvest, with the burn, but Janet's mother still searches the fields day and night.

"When I started the book, I wasn't thinking it was a crime story, more of a coming-of-age-story, a story about the loss of innocence and a fear of the future," Cuskelly says.

The story is set in the 1970s, a time of great social and cultural change.

The book touches on women's liberation, sexual freedom, Vietnam, communism, racism, and the protests against the 1971 tour by the South African rugby team, where then premier Joh Bjelke-Peterson declared a month-long state of emergency in Queensland.

"I just wanted to write about this sense of upheaval at the time, which was kind of frightening, this idea of the unknown and things being outside of your control."

Cuskelly was also keen to explore what happens in a small community when something bad happens.

Her book Wedderburn: A true tale of blood and dust, was longlisted for best debut and best true crime in the 2019 Davitt Awards.

It this book, she explored the brutal 2014 murders of Mary Lockhart, 75, her husband Peter, 78, and her son Greg Holmes, 48, by neighbour Ian Jamieson, and the effect it had on the small central Victorian town of Wedderburn not far from Bendigo.

In The Cane, the town seems to turns on itself; everyone is a suspect, the children don't trust the adults, the adults don't trust the children, and neighbours are suspicious of each other as the search for Janet continues.

"In terms of fiction writing, small towns lend themselves to all kinds of stories," she says.

"You've got a very defined set of characters, that inherent tension, most small towns have secrets they don't want people to know."

If Cuskelly didn't envision the book as a crime novel, her publishers did.

It sits alongside Jane Harper, Chris Hammer, Sarah Bailey and Garry Disher as one of the best Australian noir books of recent years.

Just as setting plays an important part in The Dry or Scrublands, for example, here, far-north Queensland becomes a sinister place. And if you've enjoyed the adaption of Candice Fox's Troppo on the ABC, The Cane will be right up your alley.

"North Queensland has this kind of Gothic element to me," Cuskelly says. "The heat, the humidity, the storms, the cyclones, that kind of thing.

"And the cane is so pervasive - at the height of its growing season, it's more than three metres tall, and there are acres and acres of it as far as the eye can see. How could you find anything in there? It just added to the menace of it all."

Cuskelly remembers reading about the real case for her essay, and again for the novel - how the event changed Mackay, how the locals still talk about the town pre- and post-Marilyn.

"Turning to fiction enabled me to explore this side of it, delve into the social aspect of it, something I really enjoyed."

Fifty years after her disappearance, Marilyn Wallman's family is still searching for answers. In a recent interview with the ABC, her brother Rex spoke of their loss.

"We have no idea what happened to her, where she went, where she is today. Nothing," he said.

While fiction such as The Cane sometimes wraps things up in a neat bow, it's a tragedy that so many real life stories never get a final chapter.