Happy Christmas

Kelly (Melanie Lynskey) and Jeff (Joe Swanberg) are enjoying their contented married life with their adorable two-year-old son Jude (Jude Swanberg). When Jeff’s younger sister Jenny (Anna Kendrick) splits up with her boyfriend, she moves to town and into their basement. In exchange, she's supposed to help Kelly with Jude and the household chores, but she turns out to be an immature drug and alcohol abuser. Her only friend in town, Carson (Lena Dunham), is also appalled and embarrassed by Jenny's antics.

Jenny starts dating Kelly and Jeff’s babysitter Kevin (Mark Webber), who retains his job since Jenny proves to be completely unreliable. When Kelly, an author, asks Jeff for time off from being a stay-at-home mom to get some writing done, Jenny wants to help her and suggests her sister-in-law write a sexy romance. As they work together on the book, with Kelly writing and Jenny suggesting story ideas, their relationship improves. Which is good, because when her relationship with Kevin takes a hit, Jenny goes off the rails.