Some treasures are best left buried . . . Scuba diving off the Tanzanian coast, husband-and-wife treasure-hunting team, Sam and Remi Fargo discover a huge ship's bell, covered in cryptic carvings. But as they struggle to first recover the bell and then decode its clues, they find they are not alone in wanting to discover its secrets. When news of the find is publicised, Mexican President Quauhtli Garza is forced to act. He knows that this bell comes from a former Confederate ship that sank off the African coast and he fears that the discovery of a missing piece of a Quetzalcoatl statuette, which was aboard the ship, will undermine his plans for Mexico's future. With Garza determined to stop the Fargos investigation at all costs, the couple are drawn into a deadly conspiracy that connects the 1883 Krakatoa explosion with an attempt to resurrect the fallen Aztec empire . . .