Four couples plan to reunite for a "marriage intervention" disguised as a fun-filled weekend at a lakeside vacation home. In an attempt to push Ruby (Cobie Smulders) and her husband Peter (Vincent Piazza) toward divorce, Annie (Melanie Lynskey) and her fiancé Matt (Jason Ritter) have gathered family and friends to address their failing marriage. Ruby's sister Jessie (Clea DuVall), her girlfriend Sarah (Natasha Lyonne), old buddy Jack (Ben Schwartz), and "baby-stranger" Lola (Alia Shawkat) engage in various games while trying to maintain the illusion of a fun weekend together. As it all falls apart, close quarters bring longstanding issues to the surface. As each couple reels from these revelations, they reach out to each other in unexpected ways, struggling to express their devotion and conceding that things may never be perfect. New bonds form and old wounds heal as all see the result when the best of intentions comes out in the most awkward fashion.