Kerry Andrew is a London-based composer, performer, writer and educator. She has a PhD in composition, has won four British composer awards and is the current BBC Ten Pieces commissioned composer. In 2014 she released Hawk to the Hunting Gone, an avian-themed alternative-folk album under the name You Are Wolf. Swansong, her debut novel, is set in the Scottish Highlands, where a London student flees after a disastrous night out.

Swansong is based on a ballad probably originating in the 17th century. What appealed to you about it?
It comes from the same root as the Swan Maiden myth – or it might do – and the version I came across was more supernatural. It’s very dark and romantic and tragic. Quite often in ballads you get a woman who’s been left very sad, so the fact that this involves a male character who is left bereft – in a very beautiful way – made it stand out.

What made you want to rework it as a novel?
As a folk musician, my interest is in taking old stories and songs and retelling them in a contemporary way, so Swansong came out of that. I’d always written – diaries, poetry, blogging – but then I started writing Game of Thrones fan fiction. At the end of 2013 I did a Faber Academy course: it was just three months online, but it was enough to kickstart me. Naturally the first 3,000 words of the novel I submitted for the course were totally scrapped…

Polly, the heroine, has a very distinctive, sarky voice. How did that develop?
I think of her as sparky as well as sarky: reckless, immature, but quite brave and up for adventure. She came incredibly naturally. I’d worked with a lot of teenagers as a composition teacher and they’re so adult in so many ways, and still kids too. A lot of young protagonists in books are coming of age at 14, 15, but often it takes a little while longer to grow up.

Going back to the novel’s supernatural element, was that hard to make work?
No, not for me, actually. I had to spook myself out sometimes – I would sit in the dark and try to put myself into Polly’s position. And then I read things like Evie Wyld’s All the Birds, Singing and I really studied how she did it. Some of my favourite books are those that feel contemporary and real but have that otherworldly element. I’m not interested in full-on fantastical: I like glimmers of it, interrupting the fabric of the real world.

You write beautifully about the Scottish landscape while staying true to Polly’s urban perspective. Did you want to develop the idea of “nature writing”?
I’m not like Polly: I know the west Highlands well and I love it there. But I don’t come from a rural background. What I was really thinking about was Romanticism – of the wild being wild and quite forbidding, not gentle – and Polly being very disdainful and it slowly working its magic on her. It was more fun to describe it through that urban lens.

What were your other influences?
I don’t think the novel’s turned out like any of these people’s writing at all, but I love Sarah Hall – she’s absolutely immense. I really like Sarah Waters, Ali Smith and Zadie Smith. And British art-house films that are often about rural landscapes: My Summer of Love, Shell and God’s Own Country, which is my favourite film.

What are the similarities – and differences – between writing fiction and music?
They’re completely different. Writing a novel is a bit like writing an opera: it’s a massive undertaking and you’re doing everything – you’re the librettist and you’re setting the scene and doing everything else.

Can you tell us about collaborating with Robert Macfarlane and Jackie Morris on The Lost Words?
It was very fortuitous. I tweeted Robert and he happened to listen to my music and asked me to do a piece for his “Wren” spell – he doesn’t call them poems. He’s said he wants them to “taste good in the mouth”, which is such a lovely way of talking about words. I think about that a lot because of setting words to music: they feel like they need to taste good when you’re singing them as well.

• Swansong by Kerry Andrew is published by Jonathan Cape (£14.99). To order a copy for £12.74 go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99