Feeling like her youth is slipping away, former high school valedictorian Leigh (Kristen Bell) quits her glamorous job in Manhattan and returns to the place she last felt happy: her hometown. After moving back in with her parents, she begins work as a lifeguard and instantly falls for the boy next door... who happens to be half her age. As the couple's summer romance heats up, Leigh must face the difficult decision of either clinging to her carefree youth or finally growing up.