70 years ago, the Munro family disappeared without a trace, leaving behind their newborn baby. When sisters Rose and Connie Doughty found her, they took her in and raised her as their own. Since then, the unsolved 'Munro Baby Mystery' has brought fame and fortune to their small island. But years later, after her sister's death and the arrival of newcomer Sophie Honeywell, Rose begins to wonder if she and Connie made the right decision all those years ago. How much longer can she cover up the lie that has sustained their community for generations? And what other secrets are hiding on the island?