Enraged, a teacher murders a young pupil. Over the years, another boy is bred for one sole purpose: to avenge his sister’s death.

The film is a recollection of an adult about the unforgettable days of the first post-war year. Klava, who lost her husband at the front, with her 12-year-old daughter Lyusya sheltered Aygul with a seven-year-old boy in her house. Aygul's son - the main character, now became a pilot, recalls his childhood in a small Kazakh city, which fell on a difficult post-war time. Flying high above the Earth, he thinks of the Russian girl Lyusya, from his distant past.

The beginning of the 30s of the last century. A leak of classified information was found at the Soviet shipbuilding plant. Arriving under the guise of a scientist, the legendary chekist Karotin begins to unravel the threads of the conspiracy of the fascist spy organization. He is helped by inexperienced but active local detectives. Mastering the basics of the counterintelligence, they fall into a situation the other one funnier.