“WHEN I was fourteen, I did something terrible. At least, that’s what some people tell me. Other people don’t think it was so bad. Or they think, at least, that it can be explained. Which apparently makes a bad thing better, in their book.”

So begins York author Sophie Coulombeau’s first published novel, Rites.

The narrator who is talking at the beginning of the book is a young man called Day. Or, to give him his full name, Damian Brady. But “back then, in the summer of 1997, I was called Day. I was fourteen years old, and I decided one day that it was about time I lost my virginity. That’s what you’re here to talk about, I presume?”

It’s a wonderfully spiky opening: challenging, slightly aggressive, and addressed directly to the reader in a way that draws you in and gets you involved right from the start. The reader becomes the investigator, trying to piece together the events of one summer night 15 years earlier that changed, forever, the lives of four teenagers.

And all that’s just for starters. Rites is told from several different points of view. There are the young people themselves – Day, Nick, Rachel and Lizzie, now all adults in their late 20s, recalling those long-ago events. There are their various parents, among them Kathleen and Michel; there is the owner of a seedy hotel, a policewoman, even a local Roman Catholic priest. All the characters talk directly to the reader, explaining, justifying. All have their own different recollection about what happened: their own motivations for telling the story. None of them deliberately lie – but they all, in one way or another, deceive themselves and the reader. Getting at the truth of what happened isn’t easy. And maybe there’s more than one truth.

What essentially happened is that the four teenage friends, bored and restless during the long summer holiday in a way only teenagers can be, make a pact that they’re going to lose their virginity. They manage to rent a seedy hotel room, pair off, and get down to it. And then one of the girls accuses one of the boys of rape… But was it rape? Or was it a misunderstanding? Or a deliberate lie, prompted by jealousy, bitterness and the desire to hurt?

Even Sophie admits she doesn’t really know. “I can’t tell you what happens, because everybody (in the novel) thinks something different happened,” admits the 28-year-old, who is studying for a Ph.D in English and related literature at York University.

It all makes for what the author Philip Pullman calls a ‘terrific’ debut novel, a “story that’s intriguing, puzzling and entirely gripping.”

That is a pretty good summary. Little surprise, therefore, that Rites should have earned Sophie the coveted title of Next Great Author after she won an Arts Council-funded literary competition for young writers under 30.

The prize was to get her book published. She’s still in a bit of a daze. It is ‘really funny’ that she won the title, she says. “But I also feel insanely lucky.”

It is not as though she hasn’t paid her dues, however. She grew up in Manchester, the daughter of Catholic parents, and wrote her first novel when she was just nine. It was called, in suitably intriguing style, 1820 Was Not All A Piece Of Cake. They had been studying the early history of mining at school, Sophie explains, and the appalling conditions of the early workers were reflected in her novel. “It included a fight in a coalmine and a cannibalistic pit pony!”

She studied English Literature at Oxford, did her Masters there as well, studied for a year in the United States, then worked for the Ministry of Justice in London and the European Commission in Brussels. Then, in 2010, she came to York to start her Ph.D.

Sophie describes herself as a lapsed Catholic, and there is a strong theme of rebellion against Catholic feelings of guilt and repression running through Rites. In some way, that reflects her own upbringing and rejection of Catholicism. As a teenager, she says, she decided it was ‘just wrong’.

But the book, and the central event at the heart of it, is certainly not based on her own life, she laughs. As a 14-year-old, she’d never have dreamed of making a pact to lose her virginity in a run-down hotel. “I wasn’t half as resourceful as that! When I was 14 I was sitting in my room listening to teeny-bop music, reading Asterix and wondering why my life wasn’t exciting.”

Probably one of the reasons she became interested in rape was because she worked on sexual offences legislation while she was at the Ministry of Justice. But Rites isn’t a book about rape, she stresses. “It is very much a matter of interpretation in the book whether what happens is rape.” Rather, it is about the unreliability of people as narrators – and about the shifting nature of truth.

It is also about the darkness that lurks deep in the heart of us all somewhere. None of her characters are particularly likeable, Sophie admits. “I call them my loathsome teenagers. Most people are not very nice.”

It’s quite a surprising statement, one she quickly draws away from. “I like people!” she says. “I find them interesting. But I try not to exclude the nastier component of people’s characters.”

Sophie’s teenagers aren’t loathsome, actually: they are just weak, or cowardly, or manipulative. But each has their own redeeming qualities, as well as their own human frailties. Each is very real.

This isn’t a warm-hearted, life-affirming novel about teenagers discovering themselves, however. It is much darker, and also much more profound, than that. In her blog, Sophie describes it as bittersweet. “But it’s heavy on the bitter and very light on the sweet,” she writes. “If you’re devoutly Catholic, you probably won’t like it. If you’re militantly atheist, you’ll probably be frustrated with it. If you’re the kind of person who enjoys certainty, clear resolution and believing that everything happens for a reason then I think you might find it uncomfortable reading. The worst thing anyone could say to me (within reasonable bounds of politeness) is, ‘Aww, yeah, I thought it was lovely’.”

It isn’t lovely. There is a ruthlessness to it, a clear-sighted lack of sentimentality about the way Sophie allows her characters to expose themselves through their own words, that is unsettling. But it is utterly un-put-downable. Don’t even pick it up if you have to get up early for work the next morning.

• Rites by Sophie Coulombeau will be published by Route on June 25, priced £12.99. It will be launched at Waterstone’s in York on Saturday, June 16, at 6.30pm.

Sophie will also talk about her book at a new ‘writers in conversation’ event at the University of York’s Berrick Saul Building at 3.30pm on Saturday June 23, as part of the York Festival of Ideas.

• Visit Sophie Coulombeau’s blog at sophiecoulombeau.wordpress.com