In 1998, the American Jorgenson family had been on a year-long road trip in Australia. On a humid, storming night, the mother - Elsa Jorgenson - vanished in an isolated stretch of Australian everglades. Elsa was never seen again. That night, twelve-year-old Lily Jorgenson was left alone and terrified in the family camper—even her teenage sister Iris is missing. When Iris comes racing back through the rain, she refuses to tell where she’s been. Lily is certain her sister is hiding a dark secret. 24-years later, Lily is a travel writer living a settled life with her son in Pennsylvania, USA. Lily and Iris are estranged, with Iris’s secret having torn them apart. When floods dredge up their mother’s backpack from the everglades, tantalising clues are uncovered, and the police reactivate the cold case. Lily returns to Australia, determined to force Iris to finally tell her secret - and to do that, she'll have to reunite with her. But when Lily unlocks the gut-wrenching events of the past, everything she thought was true about her family is about to shatter.