Aaron Falk is back.

Jane Harper's Exiles opens with the federal agent driving to fictional Marralee Valley in South Australia, for the christening of his friend's Greg Raco's son.

It's a happy occasion: since meeting in Kiewarra in Harper's first novel The Dry, where Raco was the police officer, Falk has formed a close friendship with the Raco family.

But it's also a sad occasion: it is the one-year anniversary of the disappearance of Kim Gillespie, who grew up alongside Raco and his brothers. Kim was back in Marralee for the community's annual festival, and appears to have walked out - leaving her six-week-old daughter Zoe behind.

From the first words of the prologue, reminiscent of prologues in The Dry and The Lost Man in its close and eerie attention to a particular element (in this case Zoe in her pram), I could tell I was in safe Harper hands.

When I spoke to her online last week I learnt the consistency across her five books (three featuring Falk) is a deliberate choice.

"I have a style and overall feel of the book that I'm aiming for: I want the books to feel a certain way for the reader, and have the story unravel in a similar way," Harper said.

So the familiar elements of Harper's previous novels are all there - a compelling setting, real and intriguing characters, a suspenseful plot unravelling big themes such as substance abuse, teenage drinking, domestic violence, and parent-child bonds. But as Harper said, "It's important to make each book fresh as well, and I approach each one differently ... injecting something new, with the setting or scenario or themes."

I asked what she sees as the biggest difference between Exiles and her previous novels.

"My mindset while writing was different than in the previous novels, because I knew this would be the last Falk novel. I love writing about him, so it was really bittersweet for me to bring his story to a close... Every decision was made in terms of whether it would be right for him and his story," she said.

This answer helped illuminate what I see as both the biggest strength of the novel, and its one weakness.

The one weakness is that Falk is an outsider to the Raco family and the Marralee community. In his first outing in The Dry, he returns to Kiewarra as an outcast, but he has an intimate connection to the community and its past - which raises the emotional stakes of the novel. In Force of Nature, he has no strong personal connection to the crime.

However, the narrative is split between Falk's perspective and the story as it unfolds while the main protagonists themselves are getting lost, arguing, and dying in the bush, which gives the reader direct insight into their experiences.

But in Exiles, Falk is the protagonist, and Harper has employed no structural help (apart from two chapters close to the end). This means that she "can only really tell the story from one character's point of view. One character doesn't have all the insights that an omniscient narrator would have. The reader can't really have insights that Falk himself doesn't have".

In Exiles, Falk and the reader gain many of their insights through conversations: often with Raco, but also with Kim's grieving husband Rohan, as well as Kim's ex-partner Charlie and their teenage daughter Zara.

The festival is bustling with small-town activity: Charlie is running a vineyard, and Raco has two small children, so conversations are often - realistically but conveniently - interrupted just as they seem about to reveal a key clue.

The tension kept building, and I kept turning the pages, but I didn't quite gain as intimate an insight into what it was like for the characters to grow up in this close-knit community.

That said, I got enough glimpses of the past to realise that - like in all Harper's novels - it has repercussions for the present.

"I love bringing in the past and how it impacts the present. When I'm thinking about the book I am really focusing on the end, and then I'm thinking about what has happened, and why: What has brought these people to this extreme moment? What has caused it - is it something in the past that has resurfaced?" Harper told me.

One of Exiles' connections between the past and the present is the tradition of teenage drinking. The opening night of the Marralee Valley festival is time for the local teenagers to party in the bushland next to the festival.

Charlie, Rohan, their friend Shane, and Raco, all remember it with mixed feelings, especially now they have children - daughters - of their own, and as relationships in their friendship group have been strained by time and distance.

Harper told me she was interested in "these friendships that last the distance whether they should or not. People change within friendship groups and relationships, and people outgrow them ... but sometimes that old connection refuses to die".

Falk's own relationships and friendships have been a persistent theme of the previous novels. He has had to reassess his relationship with his late father, and the novels have illustrated how Falk's dedication to work precludes most friendships and all romantic relationships.

So the biggest strength of Exiles can also be attributed to it being intended as Falk's last outing, and Harper wanting to "do him justice, and give him the ending he deserves".

A significant subplot in Exiles concerns the romance between Falk and one of the Marralee women.

Generally, in Harper's novels, the reader can rest assured that no matter the drama and uncertainty and cliffhangers along the way, the mystery will have a satisfying resolution. So I went into Exiles confident that the crime would be solved, and looking forward to the ride.

I wasn't prepared for the uncertainty of - and how invested I would feel in - Falk's romantic choices.

His blossoming relationship with this funny, complex, competent woman kept me in a different kind of enjoyable suspense, not knowing what kind of ending Harper had in mind for Falk - and especially considering his previous outings have ended with him throwing himself on a burning man (in The Dry) and jumping off a waterfall (Force of Nature).

Harper herself doesn't like to be left hanging.

"As a reader it absolutely infuriates me. I recognise it as a technique, and sometimes it can work - that question mark is really powerful," she said.

"But for me I always like to know. When you're reading a novel with a mystery, the reward is finding out at the end. And as a writer, because I plan from the end point, I always have the resolution. There's never really a good argument for not sharing that with the reader."

As a reviewer, I have plenty of good arguments for not sharing the ending. So all I will say is I very strongly recommend Exiles. And if times have seemed too hard lately to spend time in a grieving community, you can also feel reassured by Harper.

"Good crime and mystery novels have shades of dark and light. It's a question of balance, but I do feel this one has a lot more light than maybe some of the others," she said.