The action takes place in the early 1930s. A large-scale land-surveying research is underway in a remote area of Eastern Siberia. The work had almost been concluded when a wire arrives with the news of people disappearing in the locality of Yambuy. The expedition's chief and radioman decide to go in search of the lost ones. The local Evenk hunters come to their aid. Many dangerous adventures lie in store for these daring people before they find the culprit - a man-eating bear.