Lady of the Castle by Lea Goldberg

In 1947, at the end of the war, two emissaries from the Jewish community in Israel are searching for and bringing back Jewish children who survived the Holocaust. They encounter an Eastern European aristocrat who continues to keep a Jewish girl in hiding after the war has ended. They arrive on a stormy night to an old castle, which was used as a Nazi headquarters during the war, but is now a museum. Its previous owner, Count Zabrodski, was allowed to stay as the castle's keeper. They stay the night and discover by accident Lena, a Jewish girl whom Zabrodski hid from the Nazis because he was in love with her. Zabrodski doesnt tell Lena the war ended two years ago because he doesnt want her to leave him. Dora and Michael tell her the truth, which she has a hard time accepting. But she is persuaded, and leaves with them to Israel.