Uncle Zvane is assigned by the underground People's Committee of a village to deliver a number of oxes to the Partisans in the Gorski Kotar Mountains. The story tells how the old man overcomes the difficulties, and succeeds.
Bad weather, farmers who do not allow the dumping of their estate, and people who are willing to sabotage for ideological reasons, disrupt the building of hydro-power on the Neretva river. Upon completion of construction, the benefits of electricity assures people of the necessity of progress.