Every year since they can remember, Daniella, her cousin Carly, and their friends Penny and Lainie (the #SummerSisters) have spent their summers together at the Jersey Shore in the town of Ocean Park Heights, creating and completing a summer bucket list. With Carly as the mastermind, the list ranges from the silly to the practically impossible, and it's the highlight of the summer for these four best friends.

But this summer, everything is going to be different, because last winter, Carly--their leader, their glue, their everything--passed away.

As the remaining #SummerSisters try to wrap their heads around their best friend's death, life seems determined to throw more curveballs at them, threatening to split them up for good. Daniella is accepted at a prestigious music academy in New York City, Lainie learns her family is moving out of Ocean Park Heights, and Penny is distracted by a new job and a new boyfriend.

Then Daniella uncovers a treasure like no other--a bucket list for this summer tucked away in Carly's signature seashell purse. And just like that, the #SummerSisters have an opportunity to unite and fulfill Carly's last adventure for them all. But will the list be enough to hold them together for one final summer?