What happens when two identical adult twins switch places? Michelle Monaghan shows us just how sinister things can get.

In Echoes, twins Leni and Gina (both played by Monaghan) have always been ultra close — which is why it’s especially weird when Gina wakes up one morning to find that her sister has disappeared under very mysterious circumstances. But after Gina returns to their North Carolina hometown, we learn that the sisters’ relationship was even more entwined than anyone in their lives knew: They’d secretly been swapping identities since they were children. 

The mysteries surrounding the twins deepen as questions about Leni’s disappearance begin to surface, and people start to wonder just what happened to make her vanish. We’ll find out all the answers when the series premieres Aug. 19. Before then, meet the show’s most important characters — and the actors who play them — below.

Leni and Gina

It’s double trouble for Monaghan as she plays both twins. California author Gina lives with her loving husband in a giant mansion, while her horse trainer sister, Leni, is raising a daughter in their suburban North Carolina hometown. Monaghan seamlessly slips into Leni and Gina’s characters over the course of the show’s seven episodes.

Monaghan started her showbiz career as a model before making the move to the screen. Notable film roles include Kiss Kiss Bang Bang, Gone Baby Gone and the Mission: Impossible series, and TV highlights include True Detective, The Path and Messiah.

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Jack Beck

Leni’s husband, Jack, was friends with both girls in high school before he and Leni were married. Jack and Leni raise their daughter, Mattie, on their horse farm, but he seems to be running into some mysterious money issues that unravel over the course of the season.

Those sparkling blue eyes that can only belong to Matt Bomer also appear on the TV shows Chuck, White Collar, Doom Patrol and both American Horror Stories and American Crime Story. And let’s not forget Bomer’s notable big-screen contributions in the Magic Mike films.

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Charlie Davenport 

Gina and her slick therapist husband, Charlie, live in a modern Los Angeles house. He checks in on her as she heads back East following her sister’s disappearance, but it seems Charlie’s also hiding a secret from his loving wife.

Most recently seen as a powerful drug dealer wooing Mary J. Blige in Power Book II: Ghost, Sunjata has decades of experience playing rom-com boyfriends (Ghosts of Girlfriends Past), cops (The Dark Knight Rises), firefighters (Rescue Me) and, obviously, fashion designers (The Devil Wears Prada).

Sheriff Floss

Sheriff Floss has known Leni and Gina for years — and she’s sure  something strange is afoot when Leni goes missing. Despite the sisters’ best efforts, Floss goes digging into their past only to unravel the truth behind a decades-old incident that changed everything for them.

You probably know the Canadian-stage-turned-screen actor from her scene-stealing role in beloved small-town comedy Schitt’s Creek or other series including Mary Kills People, Star Trek: Discovery and Tiny Pretty Things.

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Dylan James

Gina’s high school boyfriend reconnects with Leni when he moves back to their small hometown — and not everyone is pleased about this relationship development.

An actor since childhood, Tucker’s breakout came in 1999’s The Virgin Suicides — and he’s worked steadily in film and TV ever since. In recent years, he’s played an MMA fighter in the series Kingdom, a supernatural CIA agent in the procedural Debris and a Boston gangster in City on a Hill.

Follow Tucker on Twitter and Instagram.

Claudia

The twins’ older sister, Claudia, was paralyzed in an accident as a child and lives in their North Carolina hometown. She frequently cares for her niece, Mattie, and after years of being single, she’s hoping to find a love of her own.  

Stroker is a woman of many firsts: Before she became the first actor who uses a wheelchair to win a Tony Award (for her role in Oklahoma), she was the first actor who uses a wheelchair to be nominated for a Tony, the first to star on Broadway and the first to graduate from NYU’s Tisch drama program. She was a finalist on the short-lived reality competition The Glee Project and made her scripted TV debut on Glee. You can also catch her in the final season of Ozark.

Follow Stroker on Twitter and Instagram. 

Victor 

The family patriarch, Victor, has a close relationship with Leni, Claudia and Mattie. He raised his daughters alone following his wife’s death, but he was never aware of the true nature of Leni and Gina’s relationship and has some important news to share with his family. 

A longtime actor, O’Neill is best known for parts in films including Dallas Buyers Club, J. Edgar and Traffic and TV roles in Bates Motel, 24, The Unit and The West Wing.

Follow O’Neill on Instagram.

Echoes Trailer