Plot
In 2007, 17-year-old Morgan Davidson discovers that she is pregnant by her boyfriend, Chris. She confides this to Jonah, her sister Jenny's boyfriend and Chris's best friend, who secretly has feelings for Morgan.
Seventeen years later, Chris and Morgan are married and raising their teenage daughter, Clara. Jenny and Jonah have recently reunited after years apart, and have a son, Elijah. One day, Clara encounters her classmate Miller Adams moving the city limits sign. She helps him, then drives him home. They learn that they both have aspirations of working in film.
While talking to Jenny about Miller, Clara mentions Miller's girlfriend Shelby. Jenny cautions her not to meddle in their relationship. Morgan and Jonah speak privately about his feelings for her, but she insists it is too late for them. Clara later learns that Shelby has broken up with Miller over the budding attraction between the two.
After receiving news that Chris and Jenny have died in a traffic accident, Jonah and Morgan conclude that the two were having an affair. Morgan organizes a funeral for Chris. During the service, Clara leaves to smoke marijuana with Miller. Morgan finds them and grounds Clara. In the ensuing argument, Clara questions why Morgan did not organize Chris and Jenny's funerals jointly.
Later, Jonah and Morgan locate Chris's car in a hotel parking lot, confirming the affair. Morgan beats the car before driving it home. Clara questions Morgan about the damage, but Morgan declines to explain. Clara later sneaks out to see Miller and returns to find that Morgan has destroyed the kitchen door. Jonah hands Elijah over to Morgan the next day, suspecting Chris may be Elijah's biological father. Clara confronts Jonah later and persuades him to continue his parenting responsibilities, she and Morgan agreeing to help however they can.
The next day, after moving the city limits sign again, Miller confesses to Clara his fear that if he leaves for college, nobody will look after his grandfather. At the end of the night, Clara and Miller kiss. They later convince Clara's best friend Lexie to ask out Miller's friend Efren. At home, Jonah plays Morgan a song that reminds her of a moment they shared as teenagers.
Morgan expresses disapproval with Clara and Miller's relationship, knowing that they began flirting while he was dating someone else. Morgan and Jonah later find hidden letters from Jenny to Chris, which Jonah wants to ignore, though Morgan does not. When she points out a painting that Jenny suggested she buy Chris for his birthday although Morgan hated it, they both egg it. Morgan distracts herself with remodeling, while Clara prepares college applications.
After walking in on Jonah and Morgan kissing, a mortified Clara tells Miller she wants to lose her virginity to him that night. They start to become intimate until she begins crying, realizing that her actions are only motivated by pure spite toward her mother. He stays overnight to keep her company. In the morning, Morgan finds them asleep together. He leaves, while Morgan grounds Clara.
Later that evening, Morgan hosts an awkward birthday dinner party for Clara, inviting Miller, Lexie, and Jonah. Clara and Morgan bicker before Clara announces that her dream college has accepted her with a grant. Miller leaves, upset. Clara and Lexie visit Jenny's grave to share a drink, where Morgan finds them. The next morning, Morgan tends to Clara's hangover and finally reveals the truth. Clara fears that she inadvertently caused Chris and Jenny's deaths by texting the latter, but Morgan clarifies that Chris was driving, imploring Clara not to blame herself. Clara later texts Miller to apologize, and they reunite at the movie theater. Morgan and Jonah later have sex and burn Jenny’s letters.
The family holds a party, where Miller plays a video for Clara, revealing he has been in love with her for two years and is prepared to break up with Shelby the first day they moved the city limits sign. She accepts his invitation to the prom. She and Morgan privately express mutual love and pride for each other. Some time later, Clara and Miller finish moving the city limits sign as close to his house as possible.
