Shortly after 16-year-old Nick Ormsby is orphaned and moves into a seemingly haunted old family home with his strangely nervous uncle Hilary, Nick finds hidden in his uncle's study an 18th-century diary by one Martin Coverly, who started out a scholarly naturalist and ended, inexplicably, a ruthless pirate. Soon after that, Nick is visited by Martin himself, who bids him to Shark Island in the Dry Tortugas to complete ""unfinished business."" Thus it is that Nick and his uncle set sail in Nick's small boat and end up in the 1700s, when the uncle was Martin Coverly and Nick his nephew Nicholas Coverly. Before the unfinished business is settled Nicholas is shocked and puzzled to witness his uncle's transformation, which takes them and a crew along a colorful path from a pirate ship to the legendary King Solomon's mines in Africa. But neither Nick nor the reader ever gets at what makes Martin Coverly tick, though the uncle redeems himself in the end and so frees them both to return unhaunted to the 20th century. The other characters can be described as clearly drawn stereotypes, and Nick himself is an unwavering, upright type. (""Such was the brutality and degradation of these men,"" is a typical remark.) Wibberley plays the whole adventure straight, for readers with an affinity for the square-jawed fiction as well as the high-seas adventure of the past.