Four friends Toník, Jenda, Jirka and Peťo set off against the current of the river of time on an adventurous journey into the deep past. Together they visit the Ice Age, travel through the Tertiary and Mesozoic to the very beginning of life on Earth. Along the way, they experience amazing adventures. A full-length combined film directed by Karel Zeman, which still amazes with its trick side and allows the viewer to experience incredible adventures among dinosaurs, lizards and mammoths.