"Christina, Grant, Mimi and Papa fly the Mystery Girl and take the mystery boat, Mimi, to all the Great Lakes on a wild and watery, adventurous mystery of shipwrecks, haunted lighthouses, and island intrigue!"--P. [4] of cover.
An emergency landing puts Mimi, Papa, Christina, and Grant in the middle of a mystery involving the deadly Diamond Shoals off the coast of North Carolina and shipwrecks.