Brett and Michelle Pierson (Mark Duplass and Melanie Lynskey) are a thirtysomething married couple living in Los Angeles. They have a nice home, a young daughter and a new baby, but the spark has faded and neither is particularly happy. Their well-worn routine is given a jolt, however, with the addition of Brett's best friend, struggling actor Alex (Steve Zissis) and Michelle's sister, perpetually single Tina (Amanda Peet). 

In the series premiere "Family Day," Alex is evicted from his house and forced to decide between moving back in with his mom in Detroit or crashing on his best friend's couch. While most new dads may not welcome an additional house guest, Brett is a huge proponent in Alex moving in. And, coincidentally, his eviction and subsequent move coincide with the Pierson's "family day" outing to the beach.

En route to the ocean, the group picks up Tina at the home of a guy she recently began seeing. It is clear that she hopes this new relationship will blossom, and it's just as clear that Craig (Ken Marino) is not interested in turning their fling into anything more. 

Family day brings fun in the sun, but also highlights the failing communication between Brett and Michelle. The cracks in their marriage are increasingly more visible as Brett walks in on Michelle masturbating to 50 Shades of Grey. Embarrassed by the unexpected interruption, Michelle invites Tina on the couple's routine date night, which turns into a foursome with the inclusion of Alex.

When Tina spots Craig out with another woman, all bets are off. She confronts him angrily, causing a scene in front of the outdoor restaurant. Alex comes to her rescue, causing a diversion with a monkey impression that diffuses the situation. Alex and Tina find themselves in a convenient store, where Alex soothes her pain with doughnuts and a plan for revenge. Stocked up on toilet paper and strawberry wine, the twosome return to Brett's car and share their plan (and wine) with the others.

After a booze and laughter filled rampage, the group refuels with tacos and Tina makes the decision to stay in Los Angeles, inviting herself to crash at the Pierson residence.

The final scene of the episode finds Alex and Tina eating Oreos on the front porch of Brett and Michelle's house, unlikely allies in the difficult times faced by both.