The story of a retired music professor who discovers his true origins under unusual circumstances. A metal box containing documents is found on the site of a former Nazi World War II concentration camp. It was buried in 1941 by inmate Isaac Weiss, a composer. Besides finding out that Weiss was his real father who gave him away to friends before being taken to the camp, the professor discovers the little-known truth about Judenlager Semlin camp, one of the worst Nazi execution sites in the heart of contemporary Belgrade.