Complex sentence: In September 1943 it became apparent to Plagge that the Vilna Ghetto was soon to be liquidated: all the remaining Jews in the ghetto were to be taken by the SS, regardless of any working papers they had.
Split into simpler sentences: In September 1943 it became clear to Plagge that the Vilna Ghetto was soon to be liquidated. All the remaining Jews in the ghetto were to be taken by the SS, regardless of any working papers they had.