Seattle slacker Jack (Mark Duplass) has been beating himself up over his brother's death for a year, so his brother's ex-girlfriend (Emily Blunt) — who is also Jack's best friend— offers him her father's cabin in the San Juan Islands for the weekend to clear his head. But her sister (Rosemarie DeWitt) is already there, and a bottle of tequila later one thing has led to another, even if she is a lesbian. What follows could have been played as a door-slamming bedroom farce or, in the hands of Eric Rohmer, a casual if talky exchange of partners, but in the mumblecore-adjacent precinct inhabited by filmmaker Lynn Shelton (Humpday), sex is fraught with recriminations, even if it barely lasts a minute. Blunt and DeWitt have an easy rapport that makes the heavily improvised dialogue feel natural, but the sisters are merely agents in Jack's maturation in what is ultimately a Judd Apatow film on a microbudget.