Set during the Great Depression, this historical mystery follows 12-year-old Emma as she investigates strange happenings on her family's coastal island in North Carolina. When a local fisherman is injured and whispers about a dangerous secret involving sharks, Emma must uncover the truth while facing her own fears. With her friend Jack, she explores shipwrecks, decodes clues, and learns about ocean conservation, discovering that the real secret isn't about sharks but about human greed threatening the marine ecosystem. The story blends adventure, friendship, and environmental awareness in a suspenseful coastal setting.