The focal point of Pheasants Nest is indeed that spot on Hume Highway, about two hours from Canberra, a good spot to stop if you're keen to avoid the fast food places further south, a somewhat scenic drive across NSW's highest bridge.

But it's a bridge that holds many secrets. In 1990, the decomposing bodies of two 15-year-old boys were found inside one of the 40-metre deep pylons and it was ruled death from misadventure. In 2001, a man hurled himself over the bridge after a high-speed police car chase. In 2009, after a dog brought a human leg back to the farm, dismembered body parts were found in three different locations below the bridge and a man was charged with murder.

Now Milligan, a multi-award-winning journalist, has added her dark twist to the scene with her first go at fiction.

Journalist Kate Delaney makes one mistake in Melbourne and finds herself brutalised, bound and gagged in the back of a car on her way to Sydney. She doesn't know what's in store for her.

"I'm very familiar with that stretch of road," says Milligan, who grew up in Melbourne again and now lives there again after spending eight years in Sydney.

"There's always been this sense of creepiness about it, even before I knew its history.

"I started writing this book back in 2015 after I'd come back from one of those drives. The year before I'd been working on the Jill Meagher murder story, I got the first interview with Tom Meagher, her husband, and I got to know him quite well, the whole story just stayed with me.

"I was driving through Pheasants Nest and I was thinking about all this stuff, and the story just started coming to me in my head, what if someone like Jill Meagher didn't die, and that intersection between the victim and the police, but not a traditional whodunnit, and one from the victim's perspective. I wrote three or four chapters and then life got really busy."

Milligan is an investigative journalist with the ABC, now working on Four Corners. She's best known for her coverage of historical institutional child abuse and the experience of women in the criminal justice system and parliament. With a few chapters under her belt, she soon found herself in Indonesia covering the Bali Nine executions.

"That was such an incredibly traumatic thing to cover as a journalist and when I came back I was kind of smashed by that experience and my boss at 7.30 at the time said I should try and get my head into something else ... and so I embarked on what became the George Pell investigation."

This led to her first non-fiction book, Cardinal: The Rise and Fall of George Pell, in 2019, and not long after she wrote Witness: An investigation into the brutal cost of seeking justice. Both won several awards.

She found it kind of liberating to be able to take the story of Pheasants Nest where she wanted, write her own ending.

"There was something kind of freeing about it, being able to write what I wanted, to use my imagination, it filled me with such joy," she says. "It was kind of like therapy for me and people would say to me 'your whole face just lights up when you talk about it'.

"I might say this in the book somewhere, it was like having lemonade coursing through my veins, it was so energising."

She's not ready to give up her day job just yet but there's more fiction planned.

"You get so much inspiration from being a journalist, even if you are dealing with dark things. Writing fiction was like exorcising some demons in a way."

In Pheasants Nest, Milligan was also able to explore such things as the migrant experience. Born in Ireland, to an Irish mother and a Scottish father, she moved to Australia as a child.

"I interviewed Stan Grant at the Canberra Writers Festival about his book The Queen is Dead and he touched on how the Irish were like the blacks of Europe, that it was not about skin colour, but oppression.

"It caused me to reflect on the casual racism that was around when I was growing up as a migrant kid."

She also explores the issues that law enforcement officers have to deal with when they are working on difficult cases.

"Over the years I've got to know plenty of men and women working on these kind of cases and hearing about what they go through, how horrific their jobs are at times. Their stories just stayed with me."

Milligan wants the reader to know Kate Delaney is not her - "She has some of my experiences, but she's not me at all" - but consumers of Australian media might be asking who certain characters might be loosely based on.

"Journalism used to be filled with really eccentric characters, they make for good fiction."