The Maya civilization once stretched across more than 150,000 square miles of Mexico, Guatemala, and the Yucatán Peninsula, leaving behind pyramids, temples, and palaces that still stand in the jungle. The film surveys these ruins with footage of the major sites and commentary from archaeologists and anthropologists, laying out what the stone construction, hieroglyphic writing, and astronomical calendars reveal about how the Maya organized their cities and tracked time. Its central problem is the collapse around 900 AD, when major population centers were abandoned within a few generations. The film lays out the competing explanations without settling on one: invasion and warfare, prolonged drought and deforestation, and internal political breakdown among rival city-states. Rather than building toward a single answer, it treats the Maya collapse as an open case, using the surviving architecture and inscriptions as evidence for each side of the argument. What holds the film together is the scale of what was left behind, cities substantial enough that their emptying still has no agreed-upon cause.