Lynn Shelton's Your Sister's Sister is the best argument for Mark Duplass we've had so far. Duplass has been working hard in the indie vineyard, and here he plays Jack, a bitter, unemployed Seattleite.
The brother's ex, Iris (Emily Blunt, swallowing and kind of choking on her British accent), offers Jack her family's vacation home in Puget Sound as a refuge. Unbeknownst to Jack, Iris' big sister, Hannah (Rosemarie DeWitt), is there already, recovering from the break-up of her own long-term relationship with a woman. Jack and Hannah get into the tequila, and then into the sack. Matters are complicated by Iris' hurt feelings and Hannah's hidden agenda.
Director Lynn Shelton goes for the realistically unkempt look in dress as well as bed: the wardrobe of hoods, flannels and thermals complements the wild night (spoiler: Jack comes too soon). The wit is in the slyness of the come-on: "I would be super-open to this," is Jack's passive way of trying to lure this lesbian into a man's bed.
Seeing Hannah, it's as if the call went out for a young Catherine Keener. They certainly found her. Rosemarie DeWitt had the title role in Rachel Getting Married, and was also Midge in Mad Men, the woman who catalyzed that Ozu-like passage where Don Draper was, without any warning, transfixed by a folk song about Babylon. Here, she's a lowdown moqueuse: when Jack pays her body a heavy compliment, she picks her tooth with her fingernail to show how touched she is.
Your Sister's Sister is capped with a token, petty act of rage that's meant to look existential but looks more like street vandalism. Shelton gives her actors room to play—Duplass looks sly and clever for once—but the shaggy, unfocused quality of Shelton's dramas leaves the story to go in only one direction: the realm of too-easy reconciliation and affirmation.