Sergey Ratny is an ordinary reconstruction engineer in Russia of the 26th century. Place of work: space. As a result of a shipwreck, Sergei finds himself on a planet where the level of technology does not exceed what was on Earth at the beginning of the twentieth century. Primitive cars, dreadnoughts and other balloons... True, this does not prevent the aborigines from waging a bloody war. The Russar Empire is opposed to the powerful Yastania, and at first Sergei is even mistaken for a spy. If it were not for the intervention of Zelda, a woman who lost her son in this war, Ratny would have been destined to end his life in a local dungeon. But everything turned out differently. Sergei becomes Serge, “son of Zelda,” and begins to build the first heavier-than-air devices in the history of this planet. After all, only airplanes can withstand the crushing power of enemy airships. The battle for air supremacy of the Russar Empire begins...