I loved writing from Kate’s perspective. Hers is probably the thread that changed the least through all my drafts of the book. I was able to get into her head quite quickly, and her voice flowed quite naturally, maybe because I wrote her sections in the first person. The other perspectives are so entwined that it was sometimes more challenging to write them—I had to build up the details of their lives more slowly and carefully. But I also had a lot of fun bouncing them off one another, thinking about the connections and differences between them, and all the ways they might collide. The hardest characters to write were the ones with the biggest secrets to keep!

The relationships between women—mothers, children, friends, and cousins—are so essential to The Downstairs Neighbor. Were they inspired by any of your own personal relationships? Were they challenging to write about?

I enjoyed writing about lots of different types of relationships in the book, but the ones between the women characters definitely became the heart. Luckily, the relationships I have in real life aren’t so full of drama and disaster! But I do have a lot of female relatives and friends whom I’m very close to, so that probably influenced me to explore that theme. I think it began with Kate and her mum, and Kate and her cousin—those two relationships are absolutely central to sixteen-year-old Kate’s world, and when one of those is threatened, that’s catastrophic for her. It was then interesting to set up a parallel with Steph and Freya, another mother and daughter, and to introduce a new connection between Emma and Steph, who are thrown together by circumstances. Steph and Emma started to mirror each other more and more as I wrote. It was interesting to explore the idea that they’d made judgments about one another, as neighbors, but might never have gotten beyond that (for better or for worse) if it wasn’t for Freya’s disappearance.

Without giving anything away, did you always know how the story would end? Or did the ending change during the writing process?

I always knew what the main “reveal” was going to be, in terms of the central mystery of the story, but there were lots of other things about the ending that changed. I find endings quite challenging—I love developing characters, intrigue, mystery . . . but pulling it all together and delivering on all that setup in the final pages can be quite a task! That’s where feedback is particularly important, I think. You need early readers to tell you how they feel when they reach the end of your book. And then you have to consider if that’s how you wanted them to feel! I have many people to thank for helping me find an ending that, I hope, works for the story.