A geologist engineer Yuliya disappears. Ablamov, an elderly engineer, organizes a rescue party to look after her in the mine galleries but they find nothing. Yuliya was last seen at a ceremony for award-wining miners. The newsreel crew was filming the event. Yuliya left in the middle of ceremony. Prodanov, a headstrong and quarrelsome engineer, had followed her. Suspicion falls on him. However, the film sequences shot at the ceremony reveal that Ablamov reacted suspiciously to Yuliya's exit. Detected as the murderer, Ablamov attempts to cross the border but is caught. Yuliya had discovered that the ore contained uranium. Ablamov had replaced the samples in order to prevent the development of the uranium ore deposit.
as Major Terziev
as Leytenant Kirov
as Engineer Ablamov
as Yuliya Beleva
as Lechev
as Prodanov
as Direktor
as The laboratory assistant
as Operator
as Bay Stoyan
as Lyubka
