Dr. Leighton calls Enterprise to his home on Planet Q with the promise of a new food source that could end hunger. But this is a ruse: Leighton is one of the few remaining survivors of Kodos the Executioner, who used a planetary famine to apply his own ideas of eugenics on Tarsus IV years earlier. A burned body convinced authorities that Kodos had died then, but Leighton is certain that actor Anton Karidian is Kodos. Kirk is less than amused at the deception - and then someone murders Leighton. It's not enough to accuse, but it is enough for suspicion, so Kirk arranges to strand the acting troupe, and then offers them a ride on Enterprise where he hopes to ascertain whether Leighton's accusation is true.
Spoilers ahead. Coverage follows the scope labeled below.
Complete story — includes the ending
While visiting an old friend, Kirk suspects a Shakespearean actor may actually be the murderous former governor of Tarsus IV ("Kodos the Executioner"), where Kirk grew up. Kirk invites the acting troupe aboard the Enterprise to investigate. Spock discovers that there had been only nine people who could have identified Kodos, but seven of them were murdered when the troupe was nearby. He is certain that Captain Kirk and Lieutenant Riley, the only remaining witnesses, are the next targets.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Star Trek: The Original Series season 1. HTML formatting and reference markers removed. · Content license