The Supergirl from Krypton is the title of a fictional film produced by Ace Studio about Supergirl, before her existence was known to the world. Therefore it's purely speculation and contained many inaccuracies. ("The Mystery Supergirl!")
In an attempt to market the film, several stunt doubles were hired to perform super-feats across the world and identify themselves as Supergirl, leading the world to think there really was a Supergirl. In fact, Kara Zor-El already lived in Midvale Orphanage as Linda Lee, but the world was unaware of her existence.
The fakes were exposed when Linda Lee used a fake Kryptonite meteorite on one of them, causing her to act as if she were in pain. However, the "Kryptonite" was actually green cardboard. ("The Mystery Supergirl!")
In the story, Supergirl comes from the Kryptonian city of Toz. Her ship was blasted off of Krypton with her in suspended animation, and the ship stopped working and circled the Earth for several years before a glancing blow from a meteoroid made it work again. During the film, Supergirl fights a dragon.
- The title is directly taken from the first appearance of the Kryptonian version of Supergirl, "The Supergirl from Krypton!"