A delightful adventure story that helps reconnect kids with the excitement of nature and the outdoors while raising awareness of environmental issues. Swimming in the tidal pool, Kate peers through her mask at the undersea world below. She grabs Luke's arm and points to a structure of rocks adorned with seaweed, shells, and starfish -- it looks like an underwater fairy castle! Exploring the Isles of Shoals, the two friends discover the magic along these rocky shores; while out at sea, a secret new world of adventure awaits, where pirates, ghosts, and a feisty seal are just the beginning.