Salt looks like a kitchen staple, but this film treats it as a geological and historical force. Geologists trace salt deposits back 190 million years, explaining how ancient seas evaporated to leave the vast underground beds still mined today, and how those same deposits can destabilize climate over geological time. The story moves through the Ice Age, where salt access shaped hunter-gatherer survival, into Ancient Egypt, where it preserved bodies for the afterlife and food against famine. Phoenician traders built some of the first long-distance commercial networks around salt, earning it the nickname White Gold, and the film follows that trade route by route. It closes on the present, showing how salinity differences drive the ocean's deep circulation, the so-called conveyor belt that redistributes heat and helps govern global weather. Interviews with geologists anchor each section, tying mineral science to empire-building and climate in a way that treats salt less as a seasoning than as a lever on human history.