The beginning of the 70s... Marina Rodionova from Leningrad decided to conceive a child from a donor. The grown-up son easily believed in the legend of the hero-father, who died in the line of duty. Becoming a student, the son found out about his true origin and even figured out his dad. It turned out to be Professor Pavel Konstantinovich Khlyuzdin, who for some reason did not like the girlfriend of the young hero. To soften the professor's temper and get a "pass", the young couple does everything possible so that mom and dad finally meet and fall in love.
