Because she was Jewish, Hildegard (Hilde) Grau had to perform forced labor from 1940 for the Zeiss Ikon company in Berlin-Friedenau. In around December 1942 she went into hiding, as did her mother, Gertrud Bruck, who was 64 at the time. Her helpers included the graphic designer Richard Abraham from Berlin-Spandau, and also Erich Bloch, himself persecuted as a Jew. Bloch took the mother and daughter—probably in May 1943—to his non-Jewish friend Klara Jung in Berlin-Charlottenburg, where both women were able to stay for the time being.
Since Klara Jung was also hiding Erich Bloch in her small apartment, it eventually became too crowded. The two women were able to stay in an apartment in the adjacent building, which Klara Jung was looking after because its owner had left Berlin due to the air raids. They remained there until the end of the war.
After her liberation, Hilde Grau stated she had hidden in a total of seven places. On July 2, 1945, she married one of her non-Jewish helpers, Heinz Leonhardt, who had been her partner since during the war. She then married Richard Abraham in East Berlin several years later.