Wow, it's not often you have a comic book with the main character tied up on the cover that's not Wonder Woman or Lois Lane... but this time is Supergirl's turn!
I can only guess that this was during the period that Mike Sekowsky was writing and drawing the book, and was paying no attention to continuity, and had Supergirl exposed to Gold Kryptonite that didn't permanently remove her powers, but rather caused them to "turn off" at inopportune times (to deal with that, she later went to Kandor and got them to equip her with tech to replace most of her powers).
I'll tell you, sometimes I'm amazed that it took so long for DC to kill her off.
Oh, one more thing... "kidnapping" a building?!?!? Really??? "Stealing" the building, and "kidnapping" the occupants I could buy...
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