Moscow city. Exhibits of the Museum of the Revolution, including a burnt Czech-Russian dictionary, found in 1942 in an unexploded high-explosive bomb filled with sand that pierced the roof of the pedagogical institute. The authors of the film are conducting an investigation, meeting in Czechoslovakia with citizens who worked during the Second World War at German military factories who participated in sabotaging the production of military equipment and ammunition; rescuing Soviet prisoners of war. Interviews given by: Pyotr Hron, Eduard Hotz, Anna Virtova-Shtruntsova, Maria Marek. Maria Marek from the village of Horní Jeleni tells about her husband Edmund Marek, who put a Czech-Russian dictionary in a sand bomb.