Megan (Keira Knightley) is an aimless twenty-eight-year-old living in Seattle, Washington who is in a committed relationship with her high school sweetheart and still close with her high school friends. At her friend Allison's (Ellie Kemper) wedding, her boyfriend unexpectedly proposes. She also sees her father cheating on her mother. Shocked and confused, she flees and runs into teenager Annika (Chloë Grace Moretz) and her friends outside a grocery store. After buying them alcohol, Megan plays with their skateboard. When they ask her to join them on their night out, she does.