The Cold Case Kids -- Brogan, Brycen and Heather -- are spending summer vacation hanging out at the beach and exploring Chantry Island's old lighthouse. Then they find a diary that's been hidden on the island for over a century and the summer gets strange. A rotting zombie rises from its grave. Ancient ghosts appear in the lighthouse. And the kids learn of a cryptic riddle that points to a treasure -- riches left behind by pirates of the Great Lakes. The Cold Case Kids must join forces with the undead to unravel the riddle and find the treasure . . . but they are not alone in their quest . . . THE TREASURE HUNT IS ON!