ABOUT AS STRIPPED-DOWN as a major release can get, “Your Sister’s Sister” is completely zeroed in on its three principals. There are only two other characters with dialogue, and one of them is a waitress taking an order. So that leaves about 90 minutes for three actors to invest themselves fully into a simple yet thorny story.
Jack (Mark Duplass) is one year removed from the untimely death of his brother, and he’s never fully recovered. His best friend, Iris (Emily Blunt), was also Jack’s brother’s girlfriend. At her suggestion, he gets out of his own head for a while and heads to her family’s spacious cottage in Washington’s San Juan Islands. One slight complication: When he arrives, he meets Iris’ sister, Hannah (Rosemarie DeWitt). She wasn’t supposed to be there. Hard to get away from it all with company around. Another bigger complication: On the night they meet, Hannah and Jack get plastered and have awkward, unattractive, kind of unintentional sex. They don’t make greeting cards for best friends or kid sisters about that situation, so eventually somebody’s going to have a conversation with Iris that’s more awkward than the sex.
Writer-director Lynn Shelton has purposely and convincingly made a film about the little moments between people. To the actors’ credit, Blunt and Duplass and Blunt and DeWitt seem as though they’ve known each other for years, but Duplass and DeWitt don’t share that kind of nonverbal shorthand. It’s a very believable trio, and they’re given every chance to shine individually and as a team.
Shelton has staged a handful of scenes that last an incredibly long time by contemporary standards, but there is never a dull moment. Because of the intimacy we reach with the characters, their emotions and vulnerabilities are always right there on the screen. We really see these characters working through things underneath the surface. That’s rare to find; rarer still is when it comes together this well.