An early scene in Lynn Shelton’s naturalistic comedy “Your Sister’s Sister” turns a morose, well-meaning slacker into a Peeping Tom. A year following his brother’s death, unemployed Jack (Mark Duplass) still struggles to deal with grief, anger and his personal interactions. Jack’s best friend Iris (Emily Blunt) packs him off to her family’s remote waterfront cabin so he can get his head together. When Jack arrives at night and gropes around for the house key, he spots a leggy, tousle-haired beauty flouncing through the kitchen. And his gaze lingers.
It’s appropriate that an early scene of “Your Sister’s Sister” should evoke accidental voyeurism, since the film gives the audience a similarly intimate point of view on its three protagonists. Instead of worshipfully watching the activities of larger-than-life personalities on the silver screen, “Your Sister’s Sister” is more like eavesdropping on real people through a window or a nanny-cam. Writer-director Shelton’s unhurried conversations foster a sense of personal intimacy and convey how the characters get to know themselves and each other more closely over the course of the film. “Your Sister’s Sister” aims for and achieves the goals of literary fiction more than the splashy spectacles of typical movies.
When Iris’ peeped-upon stepsister Hannah (Rosemarie DeWitt, the title character of “Rachel Getting Married”) nearly wallops Jack with an oar, the pair have an awkward first meeting. They uneasily agree to spend the night in the spacious cabin, but when neither can sleep, they end up knocking back tequila shots at 3 a.m. After they let their guards down, Hannah gradually admits to feeling emotionally shattered after breaking up with her longtime girlfriend. “I apologize if I’m barging through the doors of your privacy right now,” Jack says before praising Hannah’s personality and attractiveness, and they discover more chemistry than one would expect between a lesbian and a straight guy. Or is that just the tequila talking?
When Iris unexpectedly shows up at the cabin, the three-way dynamic becomes reminiscent of a classic sex farce, with all three characters trying to keep a secret from at least one other person. Shelton took a similar comedic approach in her previous film, “Humpday,” also starring Duplass, in which two longtime buddies consider making a sex tape to prove that they’re not squares, even though they’re both straight and one’s married. Rather than use an outlandish predicament as a pretext for slapstick and increasingly elaborate lies, Shelton would rather go small, shaking characters out of their ruts and digging deeper into their motivations. (Incidentally, several sexy comedies in recent years involve lesbians with physical attraction to guys, but “Your Sister’s Sister” doesn’t go there.)
Apart from an early scene at a memorial party for Jack’s deceased brother (which features a charming turn from stand-up comedian Mike Birbiglia), most of “Your Sister’s Sister” unfolds through soft-spoken scenes in kitchens, breakfast nooks and bedrooms. At one point Iris and Hannah talk about their father’s promiscuity — Iris’ mother was English, explaining Blunt’s accent. Jack draws a parallel with Iris’ own restless dating habits: “Let’s see: there was skinny-jeans Greg, skinny-jeans Harry, skinny-jeans Vinnie.…” Shelton doesn’t telegraph the defining traits of her characters, but allows them to gradually surface in the excellent performances of her three actors.
A drawn-out, ruminative montage prolongs the third act, as if Shelton discovered that the film was running a little short but didn’t want to impose a dramatic complication on the story. “Your Sister’s Sister” lacks the social insight and sense of risk of “Humpday,” but it still implicitly challenges its viewers to make the same kinds of interpersonal connections as its protagonists. It could be the cinematic equivalent of a weekend getaway with new friends. Just because you get to know each other’s bad habits and biggest mistakes, that doesn’t mean you like each other any less.
“Your Sister’s Sister.” With Mark Duplass, Emily Blunt, Rosemarie DeWitt. Written and directed by Lynn Shelton. Rated R. 90 minutes. At Landmark Midtown Art Cinema.