Comic Title: Challengers of the Unknown #56
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: Jun/Jul 1967
On Sale Date: April 4, 1967 Newsstand Date April 4, 1967
Source: House Ad, Sea Devils #35, Page 15

Newsstand Date April 4, 1967
Source: Direct Currents, Sea Devils #35, Page 32

Copyright Date April 4, 1967
Source: Library of Congress, Periodicals 1967

Frequency: Bi-monthly
Cover Price: $0.12
Page Count: 32
Editor: Murray Boltinoff

Title: "License to Kill"
Pages: 24

Feature(s):
Challengers of the Unknown (of Earth-1)

Writer: Arnold Drake
Artist: Bob Brown

Feature Character(s)

• Challengers of the Unknown (last appearance in Challengers of the Unknown #55; next appearance in Challengers of the Unknown #57)
• Ace Morgan (last appearance in Challengers of the Unknown #55; next appearance in Challengers of the Unknown #57)
• Rocky Davis (last appearance in Challengers of the Unknown #55; next appearance in Challengers of the Unknown #57)
• Prof. Haley (last appearance in Challengers of the Unknown #55; next appearance in Challengers of the Unknown #57)

Villain(s)

• Tino Manarry (aka Martian Ryan and Pancho Torito; last appearance in Challengers of the Unknown #55; next appearance in Challengers of the Unknown #57)
• King Taputoca and his tribe (South American natives; no further appearances)

Other Character(s)

• Princess Diza (Taputoca's daughter; no further appearances)
• Professor Lamont Drexler (behind-the-scenes; no further appearances)
• Tino's manager (next appearance in Challengers of the Unknown #57)

Cameo Appearance(s)

• Red Ryan (in a photograph)

Synopsis:
The Challengers mourn the loss of teammate Red Ryan. They finally decide to go on without him and go in search of an exotic cure for Professor Lamont Drexler. The Challengers search the jungles of South Mexico where they encounter a lost tribe of natives. The natives soon capture and drug the team with a hallucinogen.

Tino Manarry, secretly Martin Ryan Red's younger brother, also visits Mexico in search of the Challengers. With the aid of Princess Diza, the chief's daughter, Tino frees the Challs then attacks them himself. He blames the others for Red's death. The Challengers survive the attack, but Tino escapes. The Challengers then return to America with the cure for Professor Drexler.