Warsaw, September 19, 1940: a Polish officer is captured during a raid by the German army. In reality, the SS have just fallen into a trap. This man has organized everything to be arrested. His name: Witold Pilecki. His mission: to be interned in Auschwitz, to infiltrate the death camp. This film traces the story of one of the greatest resistance fighters of WWII, through the compilation of reports that the infiltrator smuggled to London from the concentration camp where he was detained.