Your Sister's Sister regards a bereaved bloke (Mark Duplass) ferried to the Puget Sound cabin of his longtime best friend (Emily Blunt), where he immediately and drunkenly tumbles into bed with her lesbian big sister (Rosemarie DeWitt). The movie, by Seattle director Lynn Shelton (Humpday), takes this contrivance—the mumblecore equivalent of high concept—and works out the results as naturalistically as possible, even making the heroes' penchant for uniquely bad ideas into an ongoing subtext. If Your Sister's Sister feels good in the moment but doesn't hold up under scrutiny, that's probably because DeWitt's character, Hannah, is so indelible (and intelligently performed) that she throws the love triangle out of balance. By comparison, the other two thwarted lovebirds seem like a stock rom-com couple in slow motion. But DeWitt's in enough scenes, so you don't notice.

  • Showing at: Laurelhurst, Living Room Theaters.
  • Best paired with: Widmer Hefeweizen.
  • Also screening: Barfly (Hollywood Theatre. 7:30 pm Saturday, Aug. 18.)