In this episode Professor Brian Cox shows how Earth's basic ingredients, like the pure sulphur mined in the heart of a deadly volcano in Indonesia, have become the building blocks of life. Hidden deep in a cave in the Dominican Republic lies a magical world created by the same property of water that makes it essential to life. Clinging to a precipitous dam wall in Italy, baby mountain goats seek out Earth's chemical elements essential to their survival. In the middle of the night in a bay off Japan, Brian explains how the dazzling display of thousands of glowing squid shows how life has taken Earth's chemistry and turned it into the chemistry of life.