When twenty-something Jenny ( Anna Kendrick ) shows up on her older brother's doorstep after a messy breakup, she brings more than just her luggage. Jeff ( Mark Webber ), a successful architect, lives a comfortably settled life in Chicago with his wife Kelly ( Melanie Lynskey ) and their toddler son. Jenny's arrival disrupts their peaceful routine, as she is a free-spirited, impulsive party girl who drinks too much and avoids responsibility. Initially, Jeff is annoyed by his sister's chaotic presence, but Kelly sees an opportunity for Jenny to help as a nanny while she pursues her own writing career. As Jenny bonds with her nephew and tentatively navigates a new romance with a local filmmaker ( Joe Swanberg ), she also strikes up a friendship with Kelly's best friend Carson ( Lena Dunham ), which leads to more reckless behavior. This intimate, improvisational comedy-drama from director Joe Swanberg explores the messy dynamics of family, the challenges of adulthood, and the unexpected ways a chaotic visitor can force everyone to confront their own happiness.