Mikhail Kalatozov, director of The Cranes Are Flying, fashioned this gripping tale of four determined geologists who set out to locate the vast diamond deposits which supposedly exist in the freezing, sparsely populated region of Yakutia. The film conveys an almost primeval sense of isolation as they trek across the frigid Siberian wastes. The letter of the title is actually a narrative soliloquy by their taciturn leader to his distant sweetheart, as he sourly eyes the budding romance of the younger geologists, played by Tatiana Samoilova (The Cranes Are Flying) and Evgeny Urbansky (Ballad of a Soldier). Once establishing the personal relationships of the geologists, Kalatozov then moves directly into his main theme, the questionable value of human sacrifice for the advancement of science. This is depicted in poetic, physical terms as the thwarted scientists begin a desperate journey back to civilization. The expedition's original purpose, to discover a diamond lode, is reduced to savage insignificance when overlayed by the dogged, but noble will to survive. Kalatozov would again set his camera down on the icy plains for Red Tent (1971), a film about a disastrous Arctic expedition, starring Sean Connery and Peter Finch.