Superman Vol.2 #21
This is the first part of The Supergirl Saga. As people in battlesuits watch within a beleaguered high-tech fortress on a devastated world, Superman finds himself being followed, but can't seem to find the person following him until he picks up the heartbeat, indicating a female. Superman catches the person from behind, and he is surprised to find a young blond-haired woman wearing a female version of a Superman costume.
Estimated Condition: VG/FN (Used)