Comic Title: Action Comics #268
Publisher: DC (National Comics Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: September 1960
On Sale Date: July 28, 1960 Copyright Date July 28, 1960
Source: Library of Congress, Periodicals 1960

Frequency: Monthly
Cover Price: $0.10
Page Count: 32
Editor: Mort Weisinger

Title: "The Mystery Supergirl"
Pages: 13

Feature(s):
Supergirl (of Earth-1)

Writer: Jerry Siegel
Artist: Jim Mooney

Reprinted In:
Supergirl Archives Vol. 1 HC (2001)
Showcase Presents:Supergirl Vol. 1 TPB (2008)
Supergirl:The Silver Age Omnibus Vol. 1 HC (2016)
Supergirl:The Silver Age Vol. 1 TPB (2017)

Feature Character(s)

• Supergirl (last appearance in Action Comics #267; next appearance in Superman #140)

Supporting Character(s)

• Miss Hart (last appearance in Action Comics #264; next appearance in Action Comics #269)

Guest Appearance(s)

• Clark Kent (last appearance in World's Finest Comics #112; next appearance in Superman #140)
• Perry White (last appearance in Superman's Pal, Jimmy Olsen #47; next appearance in Superman's Girl Friend, Lois Lane #20)

Other Character(s)

• Five phony Supergirl’s and a movie publicity man (no further appearances)

Synopsis:
Linda Lee gets a summer job at the Daily Planet. While working, she learns about a Supergirl that has been seen around the world. At first Linda believes it might be her robot, but she is able to discount this possibility. In case Red Kryptonite has affected her, she locks herself in a safe, but the Supergirl appears again.

The next day the Supergirl arrives at the Daily Planet to do an interview. Linda tricks her with a fake Kryptonite meteor into revealing that the Supergirl is a hoax. A movie studio has made a movie about a Supergirl from Krypton and the super stunts were done as a publicity stunt. When Superman returns from a space mission, he is proud of how Linda exposed the hoax.