Ellen Meeropol packs a bounty of moral dilemmas in her taut first novel,House Arrest.

There's a lot going on in House Arrest: a cult called the Family of Isis; a child with spina bifida; the Klan and neo-Nazis; and the protagonist's father was an anti–Vietnam War activist jailed for the bombing of a recruitment center. How did you get all this into just over 200 pages?

Ten years ago I read a short article about a girl under house arrest who was pregnant, and a nurse had been assigned to her for prenatal visits. At the time I was a nurse practitioner in a children's hospital and I wondered what it would be like to be this nurse, to be mandated by the court to visit the young woman under house arrest. It became a sort of what-if in my brain. A couple of years later, I thought: this is the novel I want to explore. Also, Emily [the protagonist] was a character in a short story I had written, and it was like she kept raising her hand and saying, "Hey, I am the nurse and this is my story!" The Klan scene I observed when I was in college in Ohio. I was an antiwar activist—the Vietnam War, that is; I am 64—and passionate about civil rights, and I sneaked into a Klan rally. For the novel I had to do research to make sure that kind of thing is still happening, but sometimes things that happened to you or you heard about just find their way into your fiction.

There are several characters who hold conflicting sets of beliefs. Are we supposed to sympathize with them, or does it matter?

I really like novels that illuminate injustice but acknowledge how complicated justice is. It's not black or white. Most of us don't see black or white, particularly if we try to make a difference in the world. I'm not trying to tell people how to think about my characters. I hope readers will be challenged to think about these situations. Getting us to think is one of the things that literature can do magnificently.

A lot of your fiction takes place in Maine, but you live in Springfield, Mass. Did your career take you there?

I didn't start seriously writing fiction until 10 years ago. I was a nurse when I decided I wanted to try fiction and I signed up for an online workshop, thinking that if I was really bad no one would know. I got totally hooked. In 2000, my husband and I decided to take a sabbatical—he was finishing up a memoir—and we rented a cottage off the coast of Maine. It became this place really central to my work. I like to say that I live in Massachusetts, but my muse lives in Maine. I am working on a novel that takes me back to one of the islands that's been turned into a civilian detention center. It's been very hard to write and kind of scary.