A story spanning three generations, from 1871 to 1945. When Gustav Wengler, a farmer’s son, returns from the Franco-German war in 1871, he goes to work for a precision mechanics and optical company, where he soon becomes a master craftsman. Wengler loyally promises the owner on his deathbed that his sons and grandsons will also stand by the company.

On 20th of April 1945 the Soviet army launches its attack on Berlin. The end has come for Nazi Germany and Hitler decides to commit suicide. In Prague K.H. Frank (Nazi Secretary of State and Chief of police in the Protectorate of Bohemia a Moravia) discusses with his commanders how to transform the city into an impregnable fortress, but the Praguers do not intend to wait any longer. From the early hours of 4th of May people start assembling in the streets and tearing down German signs. On the next day, the 5th of May, the uprising begins.