In the early 1800s Spanish colonists fled the Peruvian War of Independence, taking the wondrous treasures of Lima with them. Making their escape on unguarded and poorly equipped vessels, they were easy prey for the pirates swarming off the coast. A deathbed confession by the mysterious sole survivor of one such pirate crew—including a tattered map showing the location of their buried plunder—sets off a series of unsuccessful expeditions to...