Francesc Boix is a prisoner working in the photographic laboratory of Mauthausen concentration camp. He risks his life to smuggle out a series of negatives that would prove to the world the atrocities committed by the Nazis in the Austrian camp. Thanks to the help of an underground group of Spanish prisoners, Boix manages to rescue thousands of photographs that show the cruelty of the system from within. Those photographs will be used as evidence to sentence high-ranking Nazi officials during the 1946 Nuremberg trials, in which Boix acts as a key witness.

Shot in Garraf and Terrassa.