The authors' first and bestselling thriller, The Relic, hit the lists in part for its clever exploitation of extraordinary setting - the American Museum of Natural History. Just so, their fourth novel (after Reliquary) makes sprightly use of Nova Scotia's Oak Island and it notorious Money Pit - here transplanted to offshore Maine as the Water Pit on Ragged Island. The novel opens with a brisk recap of often fatal efforts over the past 200 years to recover a fabled treasure - now worth $2 billion and including a mysterious relic, St. Michael's Sword - hidden by English pirate Edward Ockham in the Water Pit. The difficulty is that the Pit, nearly 200 feet deep, was designed to flood and to kill through booby traps anyone trying to broach the treasure. Into this niftu