A disastrous flood in Perdido, Alabama, leaves behind mysterious new arrival Elinor Dammert, who soon marries into the wealthy Caskey family. But Elinor shares a secret, supernatural link to the Blackwater River that determines both Perdido's livelihood and its fate. Over the next 50 years, Elinor's influence brings prosperity, animosity, death, and reconciliation to the Caskeys.