Historian Bettany Hughes examines the Atlantis legend as told by Plato, testing it against real geological and archaeological evidence rather than treating it as pure myth. The film travels to Santorini, where the Bronze Age eruption of Thera buried the Minoan settlement of Akrotiri under volcanic ash, preserving streets and multi-story buildings that give a sense of a sophisticated society wiped out in a single catastrophic event. Hughes lays out the case that this eruption and the resulting tsunamis may have fed the story Plato later set down, weighing the timeline gaps and geographic mismatches that scholars use to argue against a direct link. Volcanologists and archaeologists working the Santorini site explain what the ash layers and excavated ruins can and cannot tell us. Rather than declaring Atlantis found, the film treats the legend as a puzzle with several plausible real-world triggers, and lets the excavated evidence from Akrotiri make the strongest case for how such a myth could have started.