The Mysterious Monk (1968)

South of Russia, autumn 1920. General Wrangel's white army is fighting with varying success with the Reds in Northern Tavria. In the white counterintelligence, a plan arises: to organize a widely ramified anti-Bolshevik underground in the rear of the Red Army. For this, the White Guards remaining in the rear of the Reds gather in the famous Matryonin Monastery.