Your Sister's Sister balances subtle comedy with a love triangle situation in a way that seems surprising given its serious premise. When Jack's (Mark Duplass) brother dies, his best friend Iris (Emily Blunt) sends him to her family's remote cabin to get some alone time and get out of his funk. Little does Jack know that Iris's sister Hannah (Rosemarie DeWitt) is also at the cabin, trying to sort through some issues of her own. A drunken introduction leads to an...interesting night, and the entire situation gets even more complicated when Iris unexpectedly drops by the next day.
While I think it has some pacing issues that crop up toward the end of the movie (montage after montage slows the pace to a crawl in the last act), I'd still recommend seeing Your Sister's Sister if you can. The leads are all extremely likeable, and there's a reality to the script (written by director Lynn Shelton) and the actors' performances that gives this movie an edge over many other films I've seen at the festival so far. This is one of those rare movies in which the dialogue feels completely natural; it hasn't been put through some screenwriting formula, because this is the way that people actually speak to each other. It's honest, legitimately funny, and its idyllic setting looks like it could be one island away from the one featured in Black Rock, which Duplass coincidentally wrote. He also starred in one of my favorite movies of this year's festival, Safety Not Guaranteed, deviating greatly from that eccentric role this time around as a much more laid back manchild kind of guy. DeWitt and Blunt totally nail the relationship between sisters, with tiny looks and mannerisms adding volumes to already stellar work from them.
IFC Films has snagged distribution rights for the movie and has it slated for a summer 2012 release, so if you're looking to escape the onslaught of summer blockbusters with a solid dramedy, I'd recommend checking out Your Sister's Sister.