Yesterday's Leningrad schoolgirl Masha Yablochkina, after a fierce blockade winter of 1941-1942, comes to the railway courses hoping to survive and gain strength. From there, the girl is sent to the construction of the Shlisselburg highway, which connects the city with the mainland and is in direct sight of German artillery. So the heroine gets into the 48th locomotive column of the special reserve NKPS, which, at the cost of the deadly risk, will have to deliver 75% of all cargo and military equipment to Leningrad.

1911, A graduate of the Institute of Noble Maidens, Sasha Meshcherskaya returns to a small provincial town. The well-being of her family is based on her relationship with her loving uncle, the owner of the arms factory Nikolai Shumilov. Sashenka's parents: Prince Ivan Sergeevich Meshchersky and Maria Ilyinichna dream of their daughter's early marriage, and she herself dreams of a brilliant career as an architect. Wanting to please her parents, Sasha makes new acquaintances and instantly plunges into a whirlpool of intrigue, where political interests are at stake above personal passions. Cold-blooded murders and blackmail, intricacies of conspiracies, daring provocateurs eluding detection - all this captivates the enthusiastic schoolgirl, who experiences mortal melancholy from the paucity of life prospects. Without noticing it, Sasha becomes an ideal target for terrorist hypnosis.