These five best friends made a Summer Sand Pact as teens and have only kept it once or twice—until they reunite decades later and renew their agreement to meet in Five Island Cove every summer.

Alice Kelton's marriage is in shambles, and while she's always thought she'd stay with her husband, after her last visit to the cove, she went back to the Hamptons and filed for divorce. She and her twins are moving to Rocky Ridge in Five Island Cove permanently, but she's not telling anyone.

Robin's husband is in Alaska for the summer, and she's pretending she's okay.

Eloise comes back to the cove every couple of weeks so she can see her new boyfriend, though she's growing tired of the distance between them.

AJ broke up with her non-committal boyfriend, and she's happier, freer, and open to another relationship, even though she lives in Atlanta.

Kelli brings her son to the cove this time, knowing her relationship with her husband is on the rocks and desperate to fix it. She plans to get some help from her sisterhood during the two weeks in the cove.

When she's followed to the beach house where the other women and their children have gathered, Kelli learns a dangerous secret thirty years in the making that could completely undo all the progress she's made...

Get ready for more secrets to come to light in Five Island Cove, and for these five women to show each other what it means to love and support someone through thick and thin.