A small volcanic island off the coast of Edinburgh unveils its dark past behind the fortified remnants. Elaborate burials excavated on Sudan's Sai Island shed light on a powerful and wealthy ancient Egyptian family. A mysterious marble head discovered off a Greek island leads to the investigation of a bronze device that might be the predecessor of mechanical computers. Marine biologists investigating the sudden disappearance of tagged sharks off California's Farallon Islands reveal the interesting connection between Great White Sharks and Killer Whales.