In July 1942, in the Second World War, the rearguard of the Russian army protects the bridgehead of the Don River against the German army while the retreating Russian troops cross the bridge. While they move back to the Russian territory through the countryside, the soldiers show their companionship, sentiments, fears and heroism to defend their motherland.
In the surreal aftermath to a plane crash at sea Dr. Iven an eminent scientist is the only survivor to be taken into the confidence of the alien rescuers. He learns that the world with its weapons of mass destruction is not ready for the wonders of the culture of the pacifist visitors. The situation is further complicated by the close relationship that blossoms between the doctor and the female alien, and due to this relationship he is the only survivor allowed to retain his memory of the events, unlike the other survivors including his wife, whose memories are erased.
A Russian engineer Petr Garin possesses a unique beam-shooting weapon that can destroy any target. His goal is to achieve world domination with the help of this weapon. Vasily Shelga is out to stop him and also to prevent others getting possession of this weapon.
The hero of the film, the world record holder in the high jump, after a car accident according to the conclusion of doctors, should forever leave the sport. But against all odds, he is doing everything possible to return to the national team. Chance brings him together with a surgeon, also fanatically devoted to his work - and the hero again wins international competitions.
