Imogen Poots has had her share of happily-ever-afters onscreen. So for her latest role, the 27-year-old English actress was seeking anything but the rom-com standard. In Frank & Lola (now in theaters) she portrays the titular Lola, a Las Vegas-based fashion designer who finds herself in a passionate love affair with Frank, a possessive chef portrayed by Michael Shannon. Both characters are flawed: Frank is jealous and suspicious, and Lola gives him reason to be. Their romance is dark and messy—and that’s precisely what drew Poots to the part.

“I was intrigued by the fact that the film is about a couple who, despite trying their best, were never going to work things out,” she said during a recent visit to InStyle’s New York City offices. “They were just human beings, and both sides messed up. There wasn’t anything they could correct, and nothing was redeemable.”

After an indiscretion on Lola’s part, things only spiral further out of control in the film. “Once you lose trust in someone, you also lose respect,” said Poots. “Everyone has that fallacy. So people might say that Lola is a siren or a femme fatale, and that Frank is an incompetent, imperfect man—but at its core, this is just a very human love story. It doesn’t put pressure on anyone. It just says, Look at what happens to this couple, and in a strange way, I think there’s something we all slightly enjoy in seeing the realness of that tragedy.”

While Poots and Shannon have an intense relationship on-camera, things were a lot more light-hearted off-screen. “It was the first time we’d worked together, and it was a great experience,” she said. “We shot most of the film in Las Vegas, over the course of just 21 days. It was a great experience—I couldn’t have asked for a greater tennis player, in a sense, than Mike. And I couldn’t have asked for a more emotionally f****d up tennis player for Lola than Frank.”

The location also played an integral part in shaping the film’s story. “We weren’t near anything that was familiar to us, and it was just a gorgeous environment to let this film fester.” It was also the perfect place to get deep into character. “The film is great, but the story itself is pretty rotten—so doing it in Vegas really lent itself to just being in a total bubble,” said Poots. “It also lent itself to having drinks whenever we wanted. In order to shoot there, we needed the casinos to be empty. So sometimes we’d start the day at 1 a.m., wrap at 1 p.m., and have a nightcap at 2 p.m., which is always great.”

The location also played an integral part in shaping the film’s story. “We weren’t near anything that was familiar to us, and it was just a gorgeous environment to let this film fester.” It was also the perfect place to get deep into character. “The film is great, but the story itself is pretty rotten—so doing it in Vegas really lent itself to just being in a total bubble,” said Poots. “It also lent itself to having drinks whenever we wanted. In order to shoot there, we needed the casinos to be empty. So sometimes we’d start the day at 1 a.m., wrap at 1 p.m., and have a nightcap at 2 p.m., which is always great.”