Your Sister's Sister

Writer/director Lynn Shelton follows up her indie breakthrough film, Humpday – an intimate, lo-fi, comic study of male sexual insecurities – with another cozily observed story about sexual secrets and disclosures. This time, Shelton includes female characters in the mix, and the new film is a three-person study instead of a two-hander. The honesty and subtlety of the situations are greatly abetted by the comfortable interplay among the three actors, who make the story’s evolution thoroughly engrossing and convincing. However, there’s also no doubt that the characters’ solitary focus on their personal needs leads, inevitably, to a solipsistic quality that, for the the most part, doesn’t feel too constrictive until the film’s overly amenable wrap-up.

The suddenly ubiquitous filmmaker and actor Mark Duplass (recent performances in other directors’ film include Darling Companion and Safety Not Guaranteed) returns for another go-round with Shelton after his co-starring turn in 2009’s Humpday. As an actor, Duplass exudes the slightly puffy, slackerish, verbal alacrity that has come to define the modern-day thirtysomething American male, which partly explains what makes his presence so in-demand. Duplass plays Jack, a Seattle denizen whose disposition has soured in the past year since his brother’s death. His best friend Iris (Blunt, also currently starring in Salmon Fishing in the Yemen), who happens to be the former girlfriend of his deceased brother, suggests Jack ride his bicycle out to her father’s remote and empty house on one of the San Juan Islands off the coast for some head-clearing alone time. But when Jack arrives – surprise! – Iris’ half-sister, Hannah (DeWitt, who played Rachel in Rachel Getting Married), has already taken up residence there. Hannah is in her own funk, having just left her female partner of the last seven years. A bottle of tequila, drunken confessions, and intoxicated judgment are the precursors to a quick roll in the hay – which, Jack realizes in the light of day he would like to keep secret from Iris. To Jack and Hannah’s further surprise, Iris suddenly makes an appearance at the island house, harboring secrets of her own. (Hannah also has a secret or two up her sleeve.)

Whereas some might have gone the screwball-comedy route with this setup, Shelton instead manages to wrangle it all into a compellingly lively and articulate dramedy – until, that is, the last-reel emotional shifts. How this ensemble piece might have worked with some other actors is beyond conceivability. Blunt, Harris, and Duplass are so perfectly in tune, so lively and natural, that their encounters are wholly believable and captivating to observe. The film’s conceits may be a bit too contrived and conventional, but nothing about these characters’ interactions are forced. Your Sister’s Sister is a welcome guest.

See “Making It Personal,” for the Chronicle’s interview with Lynn Shelton.