James Watson, co-discoverer of DNA's double helix structure, guides this account of genetics from Gregor Mendel's pea plants to the sequencing of the human genome. The film traces the race between Watson and Francis Crick against Linus Pauling and Rosalind Franklin to solve the structure of DNA in 1953, using archival photographs, reenactments, and interviews with scientists who lived through the discovery. It moves forward through the decades that followed: the cracking of the genetic code, the rise of genetic engineering, the Human Genome Project, and the ethical arguments that came with each advance, including cloning and genetic testing. Laboratory footage and interviews with researchers explain how DNA is read and manipulated in practice, not just in theory. The series treats the science as a human story as much as a technical one, following the personalities, rivalries, and controversies that shaped a field now central to medicine, agriculture, and criminal investigation.