If you are a smoker struggling to give up the habit, don't read Lucie Whitehouse's novel The House at Midnight. Virtually all her characters smoke, and not just occasionally. They light up a cigarette when they are happy, they light one up when things get black and sometimes they just light up because they want to.

Lucie explains that when she began writing this novel six years ago all her friends smoked and so did she. It was part of their lives then. As her central character, Joanna, is in some respects very much like her, putting a cigarette in her hand was another way of describing just who she, and indeed her friends were. Lucie gave up smoking two years ago, but has left the cigarette ends to smoulder their way through the book, as that is how it was when she was writing it.

Lucie read classics at Oriel College, Oxford, and got her inspiration for this, her first book, while taking a trip to the Rose Revived pub, Newbridge, one summer evening. They were driving towards the pub as dusk was falling, she said. "It was at that particular point, when the light was falling strangely on the houses we passed; I knew then that the story I was about to begin writing would be centred on a large house, seen mainly at dusk."

The House at Midnight is a dark, disturbing story which encapsulates desire, betrayal, love and friendship, in a way which is both threatening and claustrophobic. It's the story of friends who went through university together but manage to retain strong bonds after gaining their degrees.

When one member of the tight-knit group inherits a large Oxfordshire country house after the suicide of his uncle, their weekends are spent in the house enjoying each other's company without the threat of examinations hanging over them. But right from the beginning, the house begins changing everything; at first it seems as if for the better. But as the days pass and friendships become blighted by love and power, everything changes and manipulation comes into play.

Lucie says she has always been fascinated by the way power can shift between people, which is why the story is dominated by the power her various characters display.

"I'm interested in the way people can impress their will on others and manipulate to get their own way. I'm a far too easy person. I fit into other people's ways and usually go along with what they want to do. But I am very aware of the way power can shift, and the way people can use power to manipulate."

In many ways, Lucie's plot loosely echoes the power theme adopted by Robin Maughan in his novel The Servant, which was so brilliantly adapted for film by Harold Pinter, though 30-year-old Lucie says she has not seen the film, nor read the novel.

She has allowed her character Danny to be the main manipulator, though she did not plan this - it just happened.

Lucie is not a plotter; she does not work out what is going to happen to whom, or when, or even how her novel will end. She creates the characters and then lets them take over, as Danny does. Danny is the member of the group known for his flashy confidence and academic flair, which has gained him a first-class degree without effort. He was the one into drugs and who drank in excess.

"Danny came first, actually. He suddenly sprang into malevolent life as a glib, self-satisfied and very confident person who has a mind of his own. He's not taken from anyone I know - he just happened," she said. Once Danny was on the page, other characters followed. During the six years that this novel was on the back burner while she worked to earn enough money to support her writing, Lucie admits she developed and matured, and so did her characters.

"Joanna's attitude to relationships changes in the novel, just as mine did during those years I was writing it. As the years pass, there comes a time when you suddenly ask yourself what kind of life you want to live and your own moral code sets in. Suddenly you are no longer swayed by others; you have a mind of your own.

"Once, I worried about finding myself settled down with a family and marriage before I'd fully explored my career possibilities. Now, like my heroine, I feel much more comfortable about all that."

The House at Midnight has already proved so successful that Lucie, who has now moved to London, has been able to give up her day job and devote all her time to writing her second novel. This, she says, is a dream come true.

The House at Midnight is published by Bloomsbury at £12.99.