Your Sister’s Sister | Movie review

Three years ago, Lynn Shelton made the fitfully hilarious DIY gabfest Humpday, about two straight male friends who vow—in what might best be described as a game of sexual chicken—to fuck each other on camera. Shelton’s new effort, Your Sister’s Sister, can’t lay claim to such a sensational high concept, but it’s unmistakably the work of the same filmmaker. Tackling the vagaries of adult relationships through the prism of a mildly randy farce, the movie begins with Jack (Humpday star and fellow indie filmmaker Mark Duplass) biking out to the family summer getaway of best friend Iris (Emily Blunt), who dated the dead brother he’s still mourning. Romantic misadventures ensue when Jack gets drunk and sleeps with Iris’s recently dumped lesbian sister, Hannah (Rosemarie DeWitt)—a development further complicated by Iris’s unannounced arrival the next morning.

Resembling a sitcom helmed by Eric Rohmer, Your Sister’s Sister springs to life any time these damaged, loquacious bohos sit down to drink, talk, flirt or fight. Though almost entirely improvised, the dialogue crackles with wit and purpose; from a reported 30 hours of free-form chatter, Shelton has carved out a character study as revealing as a scripted feature. Much of the credit should go to DeWitt and Blunt, who share such an easy, organic repartee it’s hard to believe they aren’t really siblings. Your Sister’s Sister stumbles only in its last act, when Shelton is forced to clean up the mess her characters have made, which she does in the most tidy and conventional manner imaginable. Humpday also stumbled at the end; if Shelton sticks a landing, she’ll be a force to reckon with.