It is 1943 and the Odessa inhabitants are hiding in the labyrinth of tunnels before German occupants. Among them there are large groups of Slovak young men who fled from the fascist Slovakian State. Three of them are charged by command of the city defence led by General Amolov to find new and safer ways out of the underground. The hungry and thirsty young men have been walking for quite a long time in the dark and they are fighting because they are nervous and desperate. An explosion on the surface had filled up the tunnel and it seems they cannot be rescued. But then a flame of their kerosene lamp moves all of a sudden. The young men consider whether to use a mine which they have as an ammunition for opening the way. Somewhere above them there must be a place called Samoty (Seclusion). In the end they build a barrier from stones and with the last match they fire the mine off. The explosion makes fortunately a hole leading to the air and daily light.
Beneath Odessa and its surroundings, there are hundrerds of kilometres of tunnels which originate from the mining of shelly limestone. Its rich reserves had originated once from sedimentation on the bottom of the sea covering the Southern Ukraine in the prehistory. Odessa was occupied for two years, five months and twenty six days by Nazis and the resistance fighters were hiding in the catacombs (since 1941). Katajev, a Russian writer on whose book The defended Odessa the film is based, knew this region of the Usatovs seclusion well from his childhood.