Based on the novel by Vladimir Orlov "Salty Watermelon".

About the youth team of builders laying in the taiga railway Abakan-Tayshet. In the taiga, on the site of the future route, the youth team of Nikolai Bondarenko works. The people in the brigade are very different: the educated muscovite Vitaly, the resourceful Boris, the scribe and the romantic "Bukvar", but everyone lives together. They dream of a future route that will open the way to the Sayan Mountains.