A team of planetary engineers and scientists tries to build a universe step by step, starting 13.8 billion years ago with nothing but hydrogen gas. At an Oxford nuclear fusion lab, researchers use a robot named Mascot inside a magnetic chamber to heat hydrogen to 100 million degrees Celsius, triggering fusion reactions that manufacture helium, carbon, and heavier elements the same way stars do. The film then moves underground into Italy's Frasassi caves, where divers explore toxic, oxygen-free subterranean lakes to show what chemistry looks like without breathable air, and to NASA's Building 9, where engineers test extreme low-pressure conditions relevant to spacewalks and planetary surfaces. Each stage of the build, from raw elements to livable atmosphere, is treated as a hurdle that a planet must clear before life becomes possible, with liquid water, correct atmospheric pressure, and adequate gravity presented as non-negotiable requirements. The structure is playful but the science is grounded in real experiments and real locations rather than animation alone.