Humanity vanishes overnight, and the film tracks what happens to everything left behind, using visual effects built with input from engineers, botanists, ecologists, geologists, and climatologists. The abandoned exclusion zone around Chernobyl stands in for the first stage of decay, its villages already reclaimed by forest since the 1986 disaster emptied them. Off the coast of Maine, the film visits island communities that have gone from inhabited to overgrown in just a few decades, using them as a real-world timeline for how fast a place erases itself. Underneath New York, the story turns to the subway system, tracing how pumps that currently keep the tunnels dry would fail within days, letting groundwater turn them into canals. Bridges rust through, dams crumble, and buildings collapse floor by floor as maintenance stops and weather takes over, with each scenario built on estimates from the specialists interviewed on camera. The throughline is decay on a timetable: some structures fail in years, others hold on for centuries, and the film is mostly interested in the order things fall.