Watch The Lost Line (1970) : Full Movie Online Free The Lost Line tells the story of a film crew that sets off to explore the Engaña, an eight kilometers abandoned tunnel that crosses the Cantabrian Mountains. For two decades, political prisoners and peasants built a railway linking the South to Northern Spain. When only the rails remained to be laid, the track was abandoned, and the tunnel collapsed. Following this forgotten path, the film crew discovers a research laboratory from Saragossa University, where scientists experiment on dark matter. Through conversations with a physicist, the film tries to understand the logic of dark matter research and the motivations of a man to spend his life waiting for a sign to come from the invisible.