As a result of heir incredible - but unintentional - discoveries in Mexico and Japan (see Tractrix and Tsubute), the NWIDI team has become an unofficial resource for certain government agencies. A call from "the highest levels" sends them back to Mexico to investigate the nature and origin of mysterious radio signals emanating from a point deep below the sea off the northwest coast of Cuba. Their remote exploration of megalithic structures 2,100 meters below the surface reveal secrets from both the ancient past and the days of the Cold War.

A mysterious underwater anomaly takes the team to the Bahamas, well inside the boundaries of the infamous Bermuda Triangle, where they find themselves surrounded by a growing body of evidence that suggests alien interference with Earth's civilizations might not be limited to the past.

In this startling conclusion to the Seeds of Civilization series, one of the NWIDI team members embarks on a quest for the truth that could affect the future of all mankind.