In McCafferty’s fourth Montana mystery, Crazy Mountain Kiss, fly-fisherman and sometime PI Sean Stranaham investigates the murder of a teenage girl.

How has Stranahan, your series lead, changed since the first book?

In the first book, The Royal Wulff Murders, Sean Stranahan was a lost man recovering from divorce and searching for a place to call home. He moved west because his father had always wanted to take him west to fish and had died before they could make that trip, and Sean didn’t much care what happened to him just as long as something happened. As the sheriff, Martha Ettinger, put it, he was one of those people who would step into shit even if there was only one horse in the pasture. He was also notably sane, the center of a cast of eccentrics. Maybe too sane. He changed, or, rather, Montana changed him, for the better I hope. In the blue-ribbon rivers and his new relationships he found not only a home but a reason to live.

What gave you the idea for the Mile-High Club in Crazy Mountain Kiss?

Several years ago I helped host a dinner party in Key West and was having a drink with the tarpon-fishing guide Simon Becker, who told the story of the infamous Key West mile-high club, called Fly Key West, a service that offered “quickie” flights for couples who paid up to $350 to be flown around the island while they cavorted in a Piper Cub. The service included souvenir sheets and the option of having their couplings recorded on a voyeur cam (“by request only”), the business coming to an abrupt end in 2001 when a man and a woman in their sixties, posing as lovers, hijacked the plane to fly them to Cuba. A struggle ensued with the pilot, who crashed the plane in the Florida Straits; the plane sank, and the pilot alone survived to tell the story. “Only in Key West,” I thought at the time—but then thought, “Why not Montana?”

Why do you write in a contemporary Western setting?

The one-word answer is the characters. One of the first things that struck me upon moving to Montana, some 30-odd years ago now, was its diversity and the openness and collective humor of the people. In the East, it seemed, people tended more to stay within their socioeconomic/philosophical/religious/political/age group.

What comes next for you?

I am contracted for two more Sean Stranahan/Martha Ettinger novels, which basically means I work too much and fish too little. I do still enjoy the characters.