Director Bryan Singer's account of a doomed German plot to assassinate Hitler opens with: Based on a True Story. That's often shorthand for Warning: Balderdash Ahead, so it's worth noting that Valkyrie respects the historical record. As the film portrays, a coup attempt was organized by a band of German officers and civilians sickened by the murderous Third Reich. Initially led by a general (Kenneth Branagh), the conspiracy's leadership passed to an aristocratic colonel, Claus von Stauffenberg ...