Years of Bolshevik coup. A Soviet plane crashed in one of the sectors of the western front. Before his death, pilot Peluzin managed to reveal the secret of his invention to air observer Andrei. The dying man asked him to finish what he had started — to build an aviation oil engine. After a long search, Andrei managed to find the blueprints, which Peluzin's former flight engineer, Bogdan, was also hunting for...