Four girls are forced to spend the summer together when their moms reunite at their childhood lake house. Always-sunny Skyler is a softball star who's hiding how bad her joint pain has gotten. Always-stormy Scarlett, Skyler's twin, would much rather be hanging out with her boyfriend back home. Amelia Grace just wants to escape her conservative stepdad after he caught her kissing a girl. And homeschooled social-media star Ellie is just excited at the chance to make some friends IRL. The girls are facing a long few months together, until they find the remnants of a secret society whose rules included playing poker, wearing pearls, telling the truth . . . and accomplishing something impossible by the end of the summer. What happens next involves midnight boat rides, flaming marshmallows, sandbar parties, crushes and heartache, and a summer they'll never forget.