When Daniel's parents die, he goes to live with his grandfather on a remote gray island off British Columbia. Together they live a lonely life, hardly talking to anyone. But the loneliness lifts from Daniel when he meets a mermaid. He returns to the shore hoping to find her again, but instead sees a sea otter, which tosses him a shell. Daniel discovers a very old key inside the shell and is certain it's a gift from the mermaid. What will this magical key unlock?