• Production Code: 65
• Stardate: 5476.3
• Original Air Date: Nov 8, 1968
• Writer: Rik Vollaerts
• Director: Tony Leader
• Guest Stars:
  • Kate Woodvile (Natira)
  • Byron Morrow (Admiral Westervliet)
  • Jon Lormer (Old Man)

McCoy tells Kirk that the most recent routine medical exams of the entire crew have revealed a case of a terminal but non-contagious disease. The victim is McCoy himself. Kirk recommends that the doctor resign immediately, but before the discussion gets any further, Kirk leads Spock and McCoy on a landing party mission to the asteroid-like vessel called Yonada, carefully disguised inside to make it appear to the humanoid inhabitants that they are on the surface of a planet. Kirk finds that the "world" is controlled by a computer known by the residents of Yonada as the Oracle, and the Oracle's instructions are being taken as a religious order. The high priestess catches McCoy's eye and asks him to remain with her - an offer which, considering the doctor's current state, McCoy finds tempting.