Challengers of the Unknown (Volume 1) with a cover date of February, 1973.
Synopsis for "Isle of No Return"
This story is reprinted from Challengers of the Unknown #7.
An explorer calls on the Challengers to help him subdue three alien creatures: a giant armadillo-like creature, a giant jelly-fish, and a giant fire-breathing bird. Using their various skills and tools at their disposal, the Challengers manage to capture each one. After all three creatures are captured, aliens from Pluto arrive, and apologize for the creatures being set loose on Earth, and thank the Challengers for recapturing the monsters for them, before leaving Earth.
Appearing in "Isle of No Return"
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Locations:
- Pluto (planet) (Behind the scenes)
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Animals:
- Plutonian giant armadillo like creature
- Plutonian giant jelly-fish
- Plutonian giant fire-breathing bird
Synopsis for "Isle of No Return"
This story is reprinted from Challengers of the Unknown #6.
Answering an SOS from a boat that has struck an ice berg, the Challengers soon learn that it was a trick by aliens from outer space and are taken prisoner. They are then forces to be exhibits in the Space Circus. Forces to fight gigantic beasts from other planets, the Challengers eventually break free from their cage and free the other captive species and lead a revolt which leads to the eventual capture of the ring master. Taking the ship back to it's home planet, the Challengers turn the ringmaster over to the authorities there before being returned home.
Appearing in "Isle of No Return"
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Notes
- A one-page text piece entitled “Return of the Challengers!” gives a quick overview of the their publication history and also use the opportunity to hype Jack Kirby.