Action Comics #278 (May 1961) begins a multi-issue spanning Supergirl arc, starting with the revelation that Superman has decided to reveal the existence of Supergirl to the world. It’s been more than two years since the introduction of the Supergirl character and perhaps the writing team has run out of ways to make interesting stories out of Supergirl-acting-in-secret. They’ve given her some crushes, sent her into the past to meet Ma and Pa Kent and Superboy, and sent her into the future to be a member of the Legion of Super-Heroes, so I guess it’s about time to stop prancing around the issue and have her revealed to the rest of the world, right?
Wrong! At the very moment that Superman is going to reveal her existence to the world via a world-wide television broadcast, Supergirl discovers that her powers are gone!
This issue’s story ends with Kara considering a normal life as an adopted girl with a big question mark around if her powers will ever re-surface. We have to wait a whole month to understand how this happened, which is a nice multi-issue spanning arc complete with a decent cliff-hanger.