Fourteen-year-old Amanda is a loner, living in a small coastal town in Nova Scotia and dreaming of swimming the English Channel. When she sees an old man jumping off an inlet bridge, she dives in to save him. He introduces himself as John McRae and insists he was just going for a swim in the bitterly cold water. Amanda soon realizes that John and Bridget McRae, who live down the road, have a magical relationship with the sea and are not at all what they appear to be. Also, she comes to believe that her own life may never be the same. When John becomes ill, Amanda embarks on a quest to save him.