Once there was this thing, a movement if you please. It was known as mumblecore, named by a semi-sarcastic sound guy commenting on the lo-fi DIY quality of movies made by young filmmakers working far outside the studio system and way below anything Hollywood would call a budget. It worked in the same spirit as the French New Wave and the Danish Dogme 95, seeking to liberate film by removing a lot of the pretentiousness — from big stars to anything remotely resembling a special effect.
Whether or not this film is mumblecore is for others to decide, but it brings together two of its best practitioners, director Lynn Shelton and actor Mark Duplass, who codirected the movement’s most famous film, The Puffy Chair. In comparison, Your Sister’s Sister was shot in 12 days for measly money, and it feels like a turning point. Staying true to its thrift-store principles, it seems easily capable of pleasing a mass audience, who, let’s face it, could care less whether the director has production philosophies. Your Sister’s Sister focuses on a young man (Duplass) who is best friends with his dead brother’s former girlfriend (Emily Blunt) and desperately takes time out on an island off Seattle’s coast where he (plausibly, it turns out) ends up sleeping with his best friend’s sister (Rosemarie DeWitt). Shelton has already explored this terrain: She dug herself deep into the world of sexual taboos in Humpday, also starring Duplass, but did so at the risk of freaking out her audience. This film, playing on the margins of incest, is also alarmingly charming. You gradually sense the semi-radical agenda, but it’s also funny and touching.
Certainly, many tragically hip cineastes will consider Your Sister’s Sister a sell-out. (Megawatt star Blunt is just one strike against it.) I’m not sure it’s great or if it even represents a truthful examination of contemporary mores and manners. But I do know that DeWitt is brilliant as the manipulative vegan lesbian sister and that Blunt gets better with each film she takes on. Weirdly enough, I’m sure my enjoyment was heightened by the mere fact that this film got made and released in America by a woman true to her own ideas.