Mary Miller chronicles a Rapture-inspired cross-country road trip from the perspective of teenage Jess in her debut novel, The Last Days of California.

In the acknowledgements, you describe yourself as someone “who said she would always and only be a short story writer.”

When I began writing, I wrote flash fiction. Gradually I started building up, but the stories in Big World [2009, Short Flight/Long Drive] are still pretty short. My only previous attempts at writing a novel—which always failed miserably, because they were too episodic and rambling—were to expand those. The reason I was able to finish this novel, I feel like, is because of the structure. It takes place over a four-day period, very compressed, and I had to get the characters from point A to point B. That creates a lot of tension—they’re running behind schedule, they’re having to move, they’re in new locations every night.

Was Last Days a novel from the get-go?

I started writing around May 2011, when Harold Camping predicted the end of the world. I’d read an article in the newspaper that had very few details. There was this guy who’d taken his family on a pilgrimage cross-country, and there seemed to be no explanation for it. I just thought that was the most bizarre thing. I started wondering what would make a person take his family on this extended road trip for no reason that I could conceive of. I don’t know how I set them in Waffle House [in the opening scene], but when they hadn’t made it to Texas yet and their destination was California, I knew it would be longer than short story length.

That framework emphasizes family dynamics—and opens up exciting story lines.

Somebody suggested at one point that I try different points of view, but I think what’s interesting is a totally biased point of view. When you’re a kid, the focus is so much more on your siblings than on your parents. Your parents are there to feed you and clothe you and say they love you, but your siblings are the ones you’re fighting with and friends with. Jess, the narrator, is focused on her sister, Elise, to the exclusion of everything else. The parents are background noise. In the car, only so much can happen. They’re moving forward, but the excitement is, “What are we going to eat next?” “Can we stop and get gas?” The parents are having their own personal struggles, so they leave the girls to their own devices a lot. When I had Jess and Elise, there were so many more possibilities: who are they going to meet, and what’s going to happen? They’ve hardly been out of their home state, and everything is exotic.

You often write from the perspective of teen girls like Jess. What makes them so interesting?

I do really like to write about teenagers. I still feel like I haven’t grown up. I love to remember how I felt as a teenager, but back then I wasn’t able to articulate anything, I just knew in this vague way that I wasn’t totally happy with things as they were. Now, having some wisdom after years of... well, just after years, I’m able to give the character more insight into what she’s feeling.