Summer vacation at Pirate Island! Liza, Bill, and Jed can't believe their grandparents' wonderful surprise. The excitement begins even before they reach the island, as Grandpa gives the first clue to the unsolved mystery of a long-lost family "treasure." Whether it's their frightening run-ins with Hermit Dan, a wild and scary romp with a swooping bat, or a midnight trip into the woods, tracking the series of weird picture clues leads the children all over the island and into all sorts of adventures.