A human life unfolds from conception to old age, tracked through the biology that makes each stage possible. The film uses microscopic and time-lapse photography to show cells dividing, a fetus developing in the womb, and the body's systems, nerves, blood, muscle, bone, working together to keep a person alive from infancy through adolescence and into decline. Interviews and narration walk through digestion, respiration, and the senses, pairing plain explanation with footage of the internal processes usually hidden from view. The film treats birth and death as bookends of the same continuous biological story rather than separate subjects, following the same kind of detail into aging tissue and the body's eventual failure. It is less a single narrative than a guided tour of anatomy and physiology, built to make the ordinary workings of a human body feel as strange and intricate as they actually are.