This first feature by writer-director Sean Durkin, a big hit at the 2011 Sun­dance Film Festival, centers on an enigmatic character with a minimal back­story. Martha (Elizabeth Olsen) is a 22-year-old who has spent the past two years living in a cult community in upstate New York.

As the tale begins, she has decided to escape. She disappears into the woods and eventually calls her sister—who ­hasn't heard from her in three years—to come pick her up. Martha is secretive with her sister about where she has been, but through a complex series of flashbacks and intercuts we learn what has happened and how it has affected her.