In this routine World War II drama by Bulgarian director Doutcho Mundrov, a group of doomed POWs work together to keep their own dignity and ethical standards high. As the prisoners interact against a background of strife, imprisonment, and references to a rising Communist presence, they come to discover that there is an outside informer passing on information to the enemy. Although they face impending execution, they decide to take steps to end the informer's career.

Nine volunteers begin digging a tunnel through rugged mountain terrain. The group includes three miners. The others have come from different parts of the country for different reasons. When winter comes, a blizzard makes the road impassable and the truck with supplies cannot reach them in time. With only a hundred metres to dig, the tunnel collapsed. Everybody leaves the construction site, except the communist Damjan. In town they check in at the mine and are due to start work in two days. During these two days, one by one, they are overwhelmed with shame for leaving the tunnel, and finally return to Damjan to finish their work despite all the difficulties.

The main heroes are twin brothers. The first is responsible young fellow and excellent footballer. The second one is an undependable gambler. The police are after him. A pretty girl stands in between them. She has profoundly fallen for the footballer. By coincidence, the twins change places, which result in a formidable mess and funny situations. Ultimately, all the misunderstandings are settled and the couple re-joins.

The students Yoshkata and Petar share rooms and wartime privations in a poor man's street. Over a glass of vine, Yoshkata often talks about the stage life of genuine beauty. The student is unaware of the passion with which Vaska, the barmaid at the local pub, burns for him. Petar is a member of an antifascist combat unit. The pupil Katya loves him. Petar carries out a sabotage action and comes home wounded. Yoshkata manages to deceive the Germans who rush into their flat that they have been drinking and playing cards throughout the evening. He saves his friend. However, the secret agent notices the doctor's visits. When the police arrive to arrest Petar, Yoshkata tries to resist them and the agent shoots him dead. Petar goes underground. On the day of the liberation, all the residents of the poor man's street celebrate, and Katya and Petar happily reunited. Vaska is there, too, a baby in her arms, the fruit of her love with Yoshkata...

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.