Yael Hersonski's powerful documentary achieves a remarkable feat through its penetrating look at another film-the now-infamous Nazi-produced film about the Warsaw Ghetto. Discovered after the war, the unfinished work, with no soundtrack, quickly became a resource for historians seeking an authentic record, despite its elaborate propagandistic construction. The later discovery of a long-missing reel complicated earlier readings, showing the manipulations of camera crews in these "everyday" scenes. Well-heeled Jews attending elegant dinners and theatricals (while callously stepping over the dead bodies of compatriots) now appeared as unwilling, but complicit, actors, alternately fearful and in denial of their looming fate. ——Written by Sundance Film Festival…