A Red Army officer Polevoy possesses a navy dirk with a secret message encrypted in its handle. The second part of a message belongs to a White army officer Nikitskiy. It's up to three young friends of Polevoy to uncover the mystery.

Immediately after the prom, Olya Rusanova arrives in the city where her father worked and tragically died. Many years ago he dreamed of building a city, and now she is walking along the street bearing his name, a street without end. Having met her father’s friends, Olya learns him anew. They tell the girl how her father wanted to see large houses and wide streets on the site of the tent city. How he knew how to be friends and to love, and how longed for Olya when he broke up with his wife, who didn't agree to go with him.

Collective farmer is unanimously elected secretary of the party committee by her fellow villagers.