In the years following the end of WWII, test pilots and designers risk their lives to master new jet technologies.

The innkeeper Bessudny and his wife Eugenia are evil and greedy people. And their niece, the modest and decent Annushka, loves the landowner Milovidov. However, the envious Eugenia tries in every possible way to prevent her personal happiness.

The artificial brain Sig, created under the guidance of Professor Yavorovsky, disappeared in one of the research institutes. Meanwhile, strange phenomena are happening in the city: all the zoo animals have been released from their cages, and the books in the city's book depository have been mixed up. And Whitefish, having mastered the accumulated experience of science and fiction accumulated by mankind, creates an artificial organism himself, returns to the professor and is soon sent to the constellation Gemini.

Maxim Mezhe, a new manager, came to Zagotskotkontora. His arrival was marked by gifts from some subordinates - sycophants and swindlers. But Maxim turned out to be incorruptible, and then the swindlers began a war against him with the help of anonyms and denunciations....

1942, Polar region. The Germans are preparing to capture Murmansk. The submarine Sch-721 is considered lucky, and its captain Aleksei Strogov has the ability to extricate himself from the most difficult situations. He also develops tactics for a periscope-free torpedo attack, despite the skepticism of colleagues and management. And now, when the Happy "Pike" had to take on board the crew of another Soviet submarine, and she was on the seabed with almost no oxygen, Aleksei manages to save people and perform the operation, paying for it with his life...