It's Memorial Day weekend, the annual kickoff to summer for the Lancaster sisters. But the festivities take a deep dive when a mysterious boating accident occurs off their seaside town, sparking questions about how well the sisters know their neighbors--and each other.

Kate, whip smart and rich, lives a charmed life--if only her lawyer husband wasn't always disappearing for his next big case. Older sister Shelby, when not selling houses, is falling hard for an on-again, off-again lover. He's perfect for Shelby in many ways, and so wrong in others. And Bree, the youngest, is reeling from a recent breakup and in desperate need of her sisters. They've always been there for each other, but as secrets arise and gossip spreads like wildfire, the idyllic weekend takes a dramatic tailspin. Will this summer's troubles change their bond before their sisterhood is righted again?