It can be a mystery why some movies work and others don’t. Lynn Shelton’s “Your Sister’s Sister” is as slight as they come, a three-character relationship comedy so bare-bones as to be almost generic. Two sisters and a guy in a backwoods cabin, talking and drinking and occasionally misbehaving — that’s all there is. Yet that’s not all there is, since by the end of this graceful little emotional farce, you know these people, their hopes and their panic, and you wish them the very best.
The movie features Mark Duplass, the actor-filmmaker who seems to be in every movie these days, probably to raise money for his own low-budget chatfests. He’s an enjoyably schlumpy onscreen presence — I wouldn’t go so far as to call him a movie star — who strikes unusual sparks with his two costars, actresses who represent more traditional notions of Hollywood glamour.
Iris (Emily Blunt) and Hannah (Rosemarie DeWitt) are the sisters, drifting in and out of closeness. (They’re half sisters, actually, since Blunt’s British accent has to be explained somehow.) The movie opens a year after the death of Iris’s boyfriend, who was the brother of Jack (Duplass), who gives a drunken speech at the memorial about how just because Tom is dead doesn’t mean he was a frickin’ saint. He’s in a bad place, so Iris packs him off to her family cabin north of Seattle to clear his head.
When he gets there, Hannah has already set up shop with a bottle of tequila, mourning a breakup with her longtime girlfriend. What ensues is hardly romantic. In fact, it’s downright Hobbesian: nasty, brutish, and short in a way that both characters and audience recognize as comically true. The complications kick in the next morning, when Iris arrives and confesses to Hannah her feelings for Jack — and you can just see where this is going, into a failed Neil Simon soufflé of slammed doors and one-liners.
Except it doesn’t. “Your Sister’s Sister” proceeds with dramatic (if not real-world) logic and humor and the sort of openhearted earnestness that doesn’t preclude satire. We laugh at these people and with them, too, since they’re all intelligent enough to see the holes they’re digging themselves into. The dialogue is largely improvised but it lacks the stammer-start of classic Mumblecore; the cast has put in the necessary work of building their characters so that the lines tumble out naturally. Some of the actors (Duplass, DeWitt) are better at this than others (Blunt), but Shelton still captures the drama of good people feeling their way through a ridiculous situation.
The director’s last film was 2009’s “Humpday,” which had a similar setup (two dudes, played by Duplass and Joshua Leonard, dare each other into bed to prove their PC bona fides) but was flatter and more forced. Shelton may work better with female characters; she certainly works well with DeWitt, whose Hannah has a weary, funny edge that defuses the film’s artsier conceits. About two-thirds in, just when “Your Sister’s Sister” seems to be bogging down into slacker melodrama, a twist comes along that revs the movie’s comedic engines back up, and the energy holds until the last image, even through the tears and sisterly bonding.
It’s rare for a film to wear its low budget so lightly. Three actors and a set, yet there’s more meat on this movie’s bones — not a lot, just enough — than films that cost 100 times as much. A score by Vince Smith adds the right daubs of coloration where needed, and it only goes for indie-strum in the final moments, when I guess it’s contractually obligated. “Your Sister’s Sister” is no big deal, but that’s why it sort of is. Shelton makes it look so easy that you wonder why other filmmakers make it seem so hard.