Krystal Sutherland is the author of Amazon Prime’s Our Chemical Hearts. She is now back with her third book – House of Hollow – and it is garnering new fans at an impressive rate.

Hailed by Kiran Millwood Hargrave as ‘dark and delicious’ and by Katherine Rundell as ‘utterly gripping and deliciously strange’, this unmissable release is out today.

Can you tell us a bit about your new book House of Hollow

House of Hollow is the story of three strange sisters – the Hollow sisters – who went through a mysterious and traumatic event when they were children. They disappeared for a month and then came back with no memory of where they had been or what happened to them. They also came back slightly different – their hair and eyes changed colour, missing milk teeth grew back and they each had a small hook-shaped cut at the base of their throats.

Ten years later, the youngest sister, Iris, is trying to finish high school and live a normal life – something that is difficult to do in the shadow of her older sisters, both of whom are famous, glamorous and wild. Then the eldest sister, Grey, goes missing again and Iris and her middle sister, Vivi, have to confront and unravel the mystery of what happened to them as children so they can find and save their sister. It’s a story with glamorous catwalk models, clues hidden in walls and ceilings, doorways that lead to unexpected places, and a character with a terrible secret.

How did your writing process differ between House of Hollow and your previous two books?

All three books have had different processes. The writing of Our Chemical Hearts was – like most debut novels – fueled entirely by blind hope and naivety! I was still a student when I was writing it, so I had to snatch time first thing in the morning or in the evening before I went to sleep. You have no idea if a single other human is going to read your debut, let alone publish it. It takes a lot of guts and a sprinkling of delusion to devote so much time to a project like that.

A Semi-Definitive List of Worst Nightmares, by contrast, was fueled by wine, caffeine and a looming deadline. I shut myself in my room for months and just bled onto my keyboard.

With House of Hollow, I took my time. I luxuriated in the world I was creating. I prefer a long, slow, careful draft. I like to give my unconscious time to percolate. I like to uncover the story layer by layer, unwrapping it gently, rather than tearing through it and trying to discover all its secrets immediately.

What is the first piece of fiction you ever remember writing?

I wrote a short story when I was twelve about a boy who lived by himself in an abandoned amusement park after the apocalypse. My teacher liked it so much that she gathered four classes together for a special event and read it out loud to everyone there. It was the first time I realised I liked writing and that I was actually good at it.

Which of your minor characters do you think deserve a novel of their own?

Definitely Vivi or Grey Hollow, the older sisters of the protagonist, Iris, in House of Hollow. Vivi, the middle sister, is this underground punk rock queen playing gigs at ruin bars in Budapest and nightclubs in Berlin. Then there’s Grey, the oldest sister, the supermodel and fashion designer with a shocking secret.

I would love to write their stories – but I’m not sure a lot of what they get up to would be appropriate for a YA audience!

Which song would be the perfect soundtrack to House of Hollow’s closing scene?

I listened to On the Nature of Daylight by Max Richter over and over again when I was writing the closing scenes. It’s maybe the most mournful, haunting – and yet deeply beautiful – song. That should give you some indication of what the ending is like!

For the rest of the book, I listened to the Annihilation soundtrack on repeat, with the occasional play of ‘Disorder’ by The Haxan Cloak, which features in the movie Midsommar. I creeped myself out a lot!

Is there a question you wish authors were asked but rarely are?

‘How many unpublished and half-finished books do you have?’ I usually get something along the lines of, ‘What advice do you have for aspiring writers?’ But there is little room in that question to really highlight the amount of unseen, unloved work that goes on behind the scenes.

I wrote three manuscripts before Our Chemical Hearts. I started and scrapped two books between Nightmares and House of Hollow. For the first 30,000 words of House of Hollow, I probably wrote 100,000 words all together, trying to get the opening just right.

All this is to say – you must learn to kill your darlings, and enjoy doing it.

House of Hollow by Krystal Sutherland is out now (Hot Key, £7.99)