Two kilometers down in the Black Sea, oxygen-depleted water has preserved wooden ships for centuries instead of destroying them. Chief scientist Jon Adams leads the world's largest maritime archaeological expedition, sending remote survey vehicles across the seabed to map how the sea formed after the last ice age and to test whether that flooding could lie behind the Noah story. Along the way the team finds more than 70 shipwrecks spanning Ottoman, Byzantine, Roman, and Greek civilizations, including what the film calls the best-preserved Roman vessel ever found and the only known intact Greek warship. Divers push to depths of 100 meters, wrestle amphorae out of a Roman wreck under time pressure, and lose expensive equipment to failures that put the whole expedition at risk. The series follows the international team through the grinding logistics of deep-sea archaeology as much as the discoveries themselves, showing sonar data turning into dive plans and dive plans turning into artifacts on deck.