In the 1840s, American diplomat John Lloyd Stephens and English artist Frederick Catherwood push into the jungles of Central America chasing rumors that a lost civilization had built cities to rival Egypt or Rome. This film follows their route through Honduras, Guatemala, and the Yucatan, where they hack through overgrowth to find Copan, Palenque, and Chichen Itza still half-swallowed by forest. Catherwood's meticulous drawings, made with the aid of a camera lucida, become the first accurate record of Maya architecture and glyphs, and the film uses them alongside the ruins themselves to show how the pair's find of more than 40 cities overturned the era's assumption that the Americas had no complex indigenous past. Historians and archaeologists on camera walk through the political risk the two men faced traveling through a region gripped by civil war, and the physical toll of disease and exhaustion that nearly ended the expedition. The result is a case study in how two amateurs with a notebook and a sketchbook forced a rewrite of the historical record.