In Ninth House (Flatiron, Oct.; reviewed on this page), a broke, desperate teen gets a free ride to Yale—but magical strings are attached.

Galaxy “Alex” Stern is a dynamic but damaged character. How did you develop her?

She really arrived with her name, Galaxy Stern, speaking very loudly. I think I had a vision of her first, this haunted, hungry person. What had brought her to that state was a little bit more of a mystery, and that was something I unraveled in the draft. But I wanted her to be as much of an outsider as possible. I wanted to isolate her as much as possible. And I wanted the stakes to be as high as possible for her, because I think sometimes college stories tend to feel very low-stakes to us. So I needed Alex to have only one chance to make this work—and to have a deep divide between the life she lived beforehand, and the life she might potentially live after Yale.

What led you to write a magical Yale University saturated with powerful enemies, elitism, and privilege?

I started out coming at this from a very popcorn-movie perspective. “Wouldn’t it be fun to write a story about the secret societies at Yale? And wouldn’t it be fun if, instead of them operating like old boys’ networks, they were actually repositories of the occult and arcane magic?” But if you’re going to write a book about a place like Yale, then you have to explore ideas of class and privilege. And if you’re going to write a book about a young woman as an undergraduate in a place like that, then you absolutely have to explore issues of gender and power.

Which writers gave you your love of twisty mystery plots?

I read a lot of Stephen King when I was younger, and he continues to be a favorite author of mine. I really love psychological thrillers like those written by Gillian Flynn. And I have fallen asleep every night for the last 15 years listening to Agatha Christie mysteries, so I imagine these seeped into my subconscious too.

Ghosts play a big part in Alex’s life. What makes them so appealing?

I wanted Alex to stand at the crux of the living and the dead. I wanted her to live in that borderland. She’s so isolated that she doesn’t have a strong connection to family, or culture, or religion. I wanted her to be threadless, and to be fumbling through things, and to be lost not only in one world, which is the world of the living, but also in the world of the dead. And I’ve just always loved ghost stories. I love horror. I love ideas of the unseen. One of the things I loved about going to Yale was that, because of these societies and these beautiful old buildings and the fact that there’s a cemetery smack dab in the middle of campus, you really do get the sense of the otherworldly and the uncanny seeping through.