The 26-year-old, a regular in British period dramas (Mansfield Park, the upcoming Brideshead Revisited), told MTV that she will soon jet off to Namibia to work on the six-part series with Sir Ian McKellen and Jim Caviezel.
Atwell described the new series as "ambiguous" and reflecting contemporary issues such as security concerns.
"It's [about] this guy who gets taken into this village and everyone's got a number, not a name," she said. "It's about how he finds his way back, and what the village is. It's very ambiguous but completely different. I don't wear a corset in it, finally, in my career."
Discussing her character, the actress added: "[She] is the love interest, but it also is someone who is working for a very important corporation. And she's not what she seems.
"She turns up in the village blind, and with a number. And you don't know whether it's a joke or if she's in a parallel world."