It's been fifteen years since Kimmy Devine promised herself she'd never move back to Rocky Cape, the idyllic South Jersey beach town where she grew up. She doesn't want to relive the crushing heartbreak and scandal that ravaged her world as a teen. Her younger sister Erin shares those feelings, the wounds she caused so many years ago forever binding her and Kimmy. Yet here they are, back in their hometown: Kimmy, floundering after quitting her high-powered finance job in London to help her dad run the family's hardware stores; Erin, reeling from fertility issues and an ongoing divorce, begging to be taken seriously by her parents. The more time they spend in Rocky Cape, the stronger the pull of nostalgia, and both Erin and Kimmy slip on the past like a pair of last year's sandals, forgetting about the blisters when worn too long. As the sisters celebrate their homecoming at their parents' yacht club, a handful of familiar faces arrive to dampen the revelry. The next morning, a body is found floating nearby and long-buried secrets from their adolescence begin to emerge. Someone from the sisters' past, it seems, is out for revenge.