An estranged couple reunites on the hunt for a famed tiara, which they both intend to steal, in Ciesielski’s 1920s-set The Winged Tiara (Thomas Nelson, Aug.).

Why the Valkyrie Tiara?

I was browsing around on social media, and I think another author had posted a picture of really cool looking tiaras—and one that was incredible looking, even compared to the other ones. I read about the history and discovered that it once belonged to the Duchess of Roxburghe, who commissioned it for her marriage. It was fashioned off of the tiaras worn in Wagner’s “Ride of the Valkyries” which were very popular at the time, especially among society ladies. I just thought it would make a really, really cool story—something kind of fun and maybe about two thieves who go after the tiara.

How did you land on the idea of married thieves?

I had never done anything like that before with the characters being married. Each time I write a book, I try to challenge myself by doing something completely different. I thought it would be fun to have these two people who were legally bound to each other and who were obviously interested in each other but were pretending that they couldn’t stand each other. If they weren’t married, then they could just walk away, but I wanted them to stay together and be forced to work together while fighting their feelings.

How did you approach their backstories?

When you’re creating characters, you have to give them problems to overcome. Those problems often stem from how they grew up and the things they grew up with or without. Jasper and Esme both had similar childhoods as kind-of orphans. But they dealt with this in different ways, with Esme deciding to walk away from their romance to avoid getting hurt again and Jasper being more open to finding the kind of love that he never had. I think that provides a really interesting complexity to their relationship because they both want love but they’re just going about it in all the wrong ways.

Why set this story in the wake of WWI?

Watching Downton Abbey got me thinking about the Great War, which Americans don’t really talk about because we weren’t in it that long. I just fell in love with the period. It changed the entire landscape of society, which makes it really exciting to write about.

The tiara heist also takes Esme and Jasper on a whirlwind tour of Europe.

I love those old Indiana Jones–type adventure movies where characters hop around and you follow them on the map. I kind of had that in my head. So I hit up all these interesting places, many of which I’ve been to myself and others I had fun exploring through the characters. It was a lot fun for me to go with them to castles, champagne caves, and chateaus.