Sail to Mackinac Island, Michigan with twelve-year-old Lillia Pameroy and step back in time to meet the spirit of a lonely little girl, Clarisse, waiting for her parents to return! An unusual carriage with its elderly driver waits at the pier to transport Lillia, her little brother Charlie, and Grauntie Nora to their summer cottage. Only the cottage is a huge three-story mansion! In the third-floor attic, Lillia discovers a child's playroom. Clues from disappearing sunglasses, to life-size portraits, and a message in a bottle help Lillia reunite Clarisse with her family. The arrival of Liam with his stories of scuba diving to shipwrecks and tales of spirit ships add historical twists to Mystery Island.