For six years, Seattle-based director Lynn Shelton has been creating intimate movies that look at the lives of friends and lovers. These movies were made with a small crew (mostly made up of her friends) and encouraged a highly collaborative and improvisational approach from the actors. The success of Shelton’ 2009 film Humpday, a comedy of sexual awakening starring Mark Duplass and Joshua Leonard, proved her style could cross over to general audiences, and after directing episodes of Mad Men and New Girl, Shelton’s confidence in her abilities rose along with her status in the industry. For her latest film, Your Sister’s Sister, she’s brought a name actress into the fold: Emily Blunt plays Iris, who hopes to help her friend Jack (Duplass) get over his brother’s death by letting him stay at her family’s empty holiday cabin. But when Iris arrives at the cabin, she unexpectedly finds her sister Hannah (Rosemarie DeWitt) there with Jack. Shelton spoke with The A.V. Club about her interest in bizarre storylines, how a last-minute casting change put the film in jeopardy, and what she thinks of the French remake of Humpday.