In 1961, a group of speleologists from Piedmont went to the Pollino massif in Calabria, southern Italy, where they discovered and explored a previously unknown earth "hole" - the Bifurto abyss, which became the deepest (687 m) cave complex in Europe and the third largest in the world. The film is a visually captivating, para-documentary reconstruction of the expedition illustrating the determination and fragility of man facing the wildness and majesty of nature. The cavemen's headlamps here become the light of discovery and knowledge, although even there, in the dark depths outside of time, they are accompanied by a trace of what is happening on the surface.