The picturesque village of Redwater is a peaceful idyll on the Irish coast. Twenty years ago, a boating accident ripped the heart out of this village's close-knit community, and the truth about the tragedy was left buried out at sea. For Kat Moon (Jessie Wallace), an open-hearted woman from the East End of London, Redwater could be the key to making sense of her fractured past. She has come here to find her son, a twin taken from her at birth without her knowledge. But as Kat dives deeper into the private lives of the people here, she risks being fatally swept up in the storm she's started.