Mitosis looks simple from a distance, one cell becoming two, but Hank Green spends this Crash Course Biology episode showing how many moving parts that requires. He walks through interphase, where chromatin condenses and centrosomes prepare, then prophase, metaphase, anaphase, and telophase, tracking chromosomes and chromatids as spindle fibers and motor proteins pull them into position. A recurring "Biolography" segment breaks up the lecture with background on the scientists who worked out these stages. Green explains why the process runs on such tight regulation: a single division that gives one daughter cell an extra chromosome, or leaves one short, causes real damage, from developmental disorders to cancer. The episode closes on cytokinesis, the final pinch that splits the cell in two, and cleavage, the physical mechanism behind that split. It is a diagram-heavy, fast-paced runthrough built for someone trying to memorize the stages in order rather than just get the gist.