| The U.S.S. Enterprise is in
pursuit of an unknown alien ship which has destroyed a Starfleet base
on Cestus III. In an uncharted area of space, both the alien ship and
the Enterprise are caught by an advanced race called Metrons.
The Metrons are angry at the two ships for trespassing into their space
and believe that physical combat is the answer to finding justice.
They transport Kirk
and the alien captain, a lizard-like creature called a Gorn,
to an uninhabited asteroid to fight to the death. The Metrons promise
that the victor and his ship will be set free, while the loser will be
destroyed, along with his ship and crew.
The Gorn informs
that the base on Cestus III was destroyed because it was believed to be
a hostile intrusion on Gorn space. The Gorn is seven feet tall and much
stronger than a human, with an extremely aggressive nature, but Kirk
has the advantage of speed and agility that his opponent lacks. Kirk
manages to keep out of the Gorn's way long enough to mix local minerals
into gunpowder, which he uses in a primitive cannon to wound the Gorn
When Kirk refuses
to kill the Gorn, the Metrons decide
that there may be some hope for the human species after all. Both
captains and their ships are set free.