Captain Nikolai Zubkov was captured by the Nazis and ended up in a concentration camp near the Polish city of Czestochowa. After some time, the captain developed an escape plan and, having recruited reliable assistants, began to dig a tunnel. When very little remained, the camp commandant sensed something was wrong and sentenced the captain to death. Before his execution, Zubkov managed to draw a plan for the mine on the back of the lining of his vest, which was given to Zubkov’s friend, the pilot Mikhail Prokhorov, through the camp hairdresser, Czech Vodichka. Mikhail decides to bring his daring escape plan to completion...