 A landing party on the second planet of the star Minara, where the USS Enterprise was to pick up research personnel, comprising Kirk, Spock and McCoy, remains on the surface when a radiation storm endangers the starship and Scotty takes the Enterprise out of orbit. The Vians trap them into their lab, where these hosts feel superior enough to subject them in turn to torturous experiments for an unspecified higher purpose. After Kirk is first to be returned having suffered this trial, his wounds are healed by the empath Gem, herself unhurt, who by her touch can transfer the wounds, which then quickly, but still painfully, heal, on herself. Then they are ordered to choose the next victim among themselves, either McCoy at mortal danger or Spock at even greater risk of brain-damage. When Doc is returned badly hurt, the Vians explain their purpose, a cruel but noble test to determine an entire race s fate based on virtue the judges themselves don t display...