During the Second World War, Yann, a professional spy, returns home after carrying out a special mission at the Abwehr intelligence center. During his journey, he falls into an ambush set up by one of his fellow students from the intelligence school, who fabricates proof that he is a "mole" in the pay of the enemy. Instead of the execution of the sentence, Yann demonstrates to the NKVD officer cadets that his work is part of the conduct of the war. Yann not only manages to triumph in this unequal fight, but also to escape to finally be reunited with his wife and daughter and to rehabilitate himself.
