Truth is one of the most valuable things on earth. Getting truth is a hard challenge even nowadays, but during the Second World War it was an almost impossible one. Furthermore the risk were higher and the bet was life. Moment of truth on counterintelligence's slang means the releasing time of discovering that all your guesses were correct and you are holding a prey in your teeth. Special services of the Soviet Union had been struggling for 5 years to protect the army from enemy's spies and a great number of officers met their death trying to catch the slight sign of the Moment of Truth.
The film sets on the story about three man seeking for a group of enemy's spies in the eastern Belarussia in the summer of 1944 almost at the end of the WWII. The plot of the film is based on documents of that time (of course, real names, dates and numbers are replaced) that were completing the book of the same title by Vladimir Bogomolov. The Moment of Truth is a masterpiece of Russian literature and one of the first stories, that tells about special services of soviet times.
There are lots of myths the world based on stories about soviet intelligence but this seems to be the nearest to the truth. Moreover the book deviates from the majority of tales about the war because it doesn't contain soviet pathos and any ideological overtones.
The grate amount of literature tells as about the heroism of common solder (in British tradition called Tommy) at the forefront, but usually forgets about espionage in the rearward. This story is quite disparate. The fate of counterintelligence officers during WWII was not a piece of cake. They died frequently but continued their work even if they hadn't much time, resources or evidence.
All in all, I would like to say that the film and the book are worth our attention. "Make love, not war" people used to say in the second half of the XXth century. That is reasonable but the humanity should not consign The Second World War to oblivion in order to prevent repeating of such a woeful occasion.