The film is set in 1920 in the Volga region during the Civil War. The story of the heroic struggle of the crew of an armored train.

Based on the popular comedy novel, as well as many international anecdotes about Nasreddin Hodja, a witty Muslim traveler.

To climb Mount Kamir-Sar, whose inaccessible summit, according to the findings of young scientist Artashes Malyan, contains a rare deposit of mercury and silver, an expedition led by Malyan is organized despite the opposition of the venerable Professor Daniel-bek. Information about the daring expedition of Soviet scientists reaches Alvarets da Cortez, the owner of one of Europe's largest chemical companies. In his youth, he visited this peak and, in order to hide the discovered metals, threw the Russian scientist Shelagin into the abyss, silencing Daniel-bek. Foreign intelligence is tasked with disrupting the expedition...