Natira was a Fabrini high priestess, leader of the inhabitants of Yonada. It was her responsibility in the Fabrini society to consult the Oracle for the guidance of her people.
In 2268, when the USS Enterprise was ordered by Starfleet Command to investigate an asteroid on a collision course with a Federation planet, it was discovered that the object was not natural but a gigantic spaceship. The landing party beamed down on the inner «surface» but were captured by powerful guards. Natira had the landing team brought inside where Kirk discovered that the «people of Yonada» were unaware of their situation.
As Kirk and Spock searched for the controls to redirect the ship, Natira and Dr. McCoy, who had a terminal illness, fell in love so deeply that McCoy wanted to stay on Yonada when the Enterprise left. He accepted the "instrument of obedience" that allowed the computer to control the people on Yonada. When McCoy found the control instrument, the computer shocked him so that he would not be able to inform the Enterprise. Kirk and Spock returned to the ship and explained the history of the Fabrini and that Yonada was actually a multigenerational spaceship, not a true world. Natira did not believe them at first, but did not call her guards. When she asked the Oracle about what she had been told, the Oracle began to torment her through her instrument and knocked her out. She agreed to help Spock remove the instrument. McCoy told them where the ship's controls were to be found and they redirected the ship. In examining the computer, Spock found a cure for McCoy's illness. McCoy and Natira tearfully parted ways. She to lead her people to the promised land, and McCoy to continue his duties as a Starfleet doctor. (TOS: "For the World is Hollow and I Have Touched the Sky")