A sudden blow is always terrible. And if it is inflicted by aliens from the depths of space, then there is practically no chance of repelling it. The ruins of the largest cities are smoking after terrible explosions, combat lasers are shooting from orbit, UFOs dominate the sky, and enemy troops are roaming the surface of the planet, as if at home. Cousins Svyatoslav and Stanislav Kraezhogov, who while fishing saw how an unknown flying object destroyed a helicopter in the air, understood one simple truth: if people surrender, they are doomed. The brothers' hands grow from where they need to, therefore, starting with the manufacture of homemade weapons against aliens, they become indispensable assistants to scientists and designers who are building an air defense network throughout the Earth. Air defense for UFOs...