On a windswept British coastline, the tide deposits an unexpected gift... It was the cry that she first noticed, the plaintive wail that called to her over the crash of winter waves. Wrapped only in a sealskin, the baby girl looks up at Effie and instantly captures her heart. She meant only to temporarily foster the young orphan, but when news reaches Effie that her husband has been lost at sea, and months pass without anyone claiming the infant, she embraces her new family—her son, Jack, and her adopted daughter, Morna. Effie has always been an outcast in her village, the only granddaughter of a woman people whisper is a witch, so she's used to a solitary existence. But when Midsummer arrives, so, too, does a man claiming to be Morna's father. There's no denying Lachlan is the girl's kin, and so, Effie is surprised when he asks her to continue looking after his daughter, mysteriously refusing to explain why. She agrees, but when he returns six months hence, she pushes him for answers. And Lachlan tells a story she never anticipated... one of selkies, legend, and the power of the sea...