David Attenborough spends an hour with the insects he considers among the most successful on the planet: ants. The film centers on the Argentine ant, a species that has spread far beyond its native range and formed supercolonies that stretch for thousands of miles along the Mediterranean coast and through parts of California, with worker ants from colonies hundreds of miles apart treating each other as nestmates rather than rivals. Attenborough visits researchers tracking how these supercolonies form, why the ants cooperate on such an enormous scale, and what happens when they meet ant societies that have not been so thoroughly conquered. Macro photography puts the viewer at ant height, following trails, nests, and the constant traffic of a colony at work, while Attenborough's narration walks through the biology of chemical communication, caste systems, and colony defense. The film treats the ants less as curiosities than as a rival civilization, one whose scale and organization rival anything built by vertebrates, and closes on the open question of what limits, if any, a supercolony actually has.