Arnold Horn, a young idealistic chemist, discovers a compound that can be used for the production of an effective deadly poisonous gas. Against his will the chemical factory starts production of the poison gas to increase the value of their shares.

After graduating from college, Natasha returns to Kamchatka, where she spent her childhood and youth. The girl arrives at the geological group of engineer Rozhnov and here she meets her childhood friend Kirik, the expedition guide. A small group of geologists will have to move to the south of Kamchatka, where there should be oil. On the way, the expedition ends up in the area of ​​the active Klyuchevsky volcano, as a result of which the horses scatter and all the group’s property is destroyed. The group's already unenviable position is aggravated by heavy snowfall. Natasha makes an independent decision - and goes for help to the nearest collective farm, which is located two hundred kilometers from the group...

The film is about the dramatic events of the early years of the Bolshevik Revolution. Based on the play of the same name by Vladimir Bill-Belotserkovets.