Comic Title: Adventure Comics #307
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: April 1963
On Sale Date: February 28, 1963 Newsstand Date February 28, 1963
Source: House Ad, Sugar and Spike #46, Page 30

Copyright Date February 28, 1963
Source: Library of Congress, Periodicals 1963

Frequency: Monthly
Cover Price: $0.12
Page Count: 32
Editor: Mort Weisinger

Title: "The Secret Power of the Mystery Super-Hero"
Pages: 13

Feature(s):
Legion of Super-Heroes (of Earth-1)

Writer: Edmond Hamilton
Artist: John Forte

Reprinted In:
Adventure Comics #500 (1983)
Legion of Super-Heroes Archives Vol. 2 HC (1992)
Showcase Presents:Legion of Super-Heroes Vol. 1 TPB (2007)
Legion of Super-Heroes:The Silver Age Omnibus Vol. 1 HC (2017)
Legion of Super-Heroes:The Silver Age Vol. 1 TPB (2018)

Feature Character(s)

• Legion of Super-Heroes (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Cosmic Boy (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Saturn Girl (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Colossal Boy (last appearance in Adventure Comics #306; next appearance in Adventure Comics #309)
• Invisible Kid (last appearance in Adventure Comics #305; next appearance in Adventure Comics #310)
• Brainiac 5 (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Sun Boy (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Bouncing Boy (last appearance in Adventure Comics #306; next appearance in Adventure Comics #308)
• Element Lad (Jan Arrah; uses the alias "Mystery Lad" in this story; origin revealed; joins the Legion of Super-Heroes in this story; next appearance in Superman's Pal, Jimmy Olsen #70)

Villain(s)

• Roxxas (a space pirate; next appearance in Superboy #211)
• Roxxas’s gang of space-pirates (no further appearances)

Other Character(s)

• Two unnamed rejected Legion applicants (no further appearances)
• The inhabitants of planet Vuruna and planet Oranz (no further appearances)
• The inhabitants of planet Trom (natives of Element Lad’s home planet; appear in flashback only; all have been killed by Roxxas by the time of this story; no further appearances)

Cameo Appearance(s)

• Superboy (as an image)
• Bizarro-Superboy (in an image)

Comments:
The Legion of Super-Heroes is mistakenly said to exist in the 21st century in this story.

Synopsis:
Desperate for aid in their upcoming battle against the space pirate Roxxas, the Legionnaires interview several new applicants. One in particular, "Mystery Lad", volunteers to demonstrate his ability to only one member, Saturn Girl, provided it be kept a secret. She then recommends him for membership.

Voted in, Mystery Lad fights alongside the Legion as they comb the galaxy for members of Roxxas’s gang, and vaguely demonstrates his secret power several times. Finally, he realizes that Roxxas is really after him, and leaving his teammates behind, surrenders to the villain. Then he uses his power, that of transmutation, to destroy the pirate’s ship, and the Legion captures the villain and his band.

Mystery Lad is revealed as the last of a race whose members could transmute the elements, and who were wiped out by Roxxas and his followers. When the other Legionnaires realize Mystery Lad's real power, Cosmic Boy rechristens him Element Lad.