While investigating the theory of creation, the U.S.S. Enterprise is caught inside an energy/matter tornado and pulled to the center of the galaxy. All computer systems fail and the crew begins to lose consciousness when a devil-like creature named Lucien appears on the bridge. The creature repairs the ship's systems and takes the crew to explore his planet, Megas-Tu, but almost immediately returns them to the ship.

The crew begin to experiment with magic after the encounter, much to Spock's dismay. The Megans begin to take notice of the crew and return to the ship in phantasm form. They return the Enterprise bridge crew to their planet in a witch-hunt trial where Lucien is accused of bringing evil to Megas-Tu.

Spock and Kirk defend the crew and Lucien, but their arguments fail and Kirk is forced to use his new magic against the prosecutor. Kirk explains that the Megans can only win if they become like the Earthlings they fear. Kirk then tells the jury that he will give his own life for an alien's rights, which impresses the Megans. They learn that Lucien was the basis for Earth's original conception of the devil, and the Megans, realizing that the Enterprise's visit to their dimension was an accident, help the crew to return to their galaxy.

Cast:

William Shatner as James T. Kirk
Leonard Nimoy as Spock
DeForest Kelley as Leonard H. McCoy
James Doohan as Montgomery Scott
Nichelle Nichols as Uhura
George Takei as Hikaru Sulu

Guest Cast:

Ed Bishop as Megas prosecutor
James Doohan as Lucien

Creative Staff:

Written By: Larry Brody
Director: Hal Sutherland