Decline and Fall Broadcast February 10th 1968
Mission Date 3656 the Endeavour is on routine patrol on the outskirts of Commonwealth space on the alert for Tellurian incursions when it encounters a jettisoned jump engine core from the CSS Enterprise. The Enterprise was under the command of Captain J.T.Kirk (guest star William Shatner), whom Reynolds knew during his naval academy days. Spock traces a path of debris back to a planet in a previously unexplored system.
The Endeavour picks up a television broadcast, with black and white video footage of what appears to be a Roman gladiatorial fight in an arena. The "barbarian" gladiator they see killed is named Fred Freiburger, identified by ship's records as one of the Enterprise’s flight crew. The broadcast also mentions the first citizen Kirquios.
Reynolds, Holmes and Fynely beam down to the planet to investigate. They are captured and brought before Octavius (guest star Douglas Wilmer), who asks them if they are "children of the stars like the Sun". Optimus explains he was a Senator until he heard the "words of the Sun" and was made a slave. Although another slave, Flavius (David Prowse), suggests killing the landing party, Octavius decides the landing party poses no threat.
That night Octavius tells the children of the group of runaways, and so incidentally the landing party, the forbidden tales of the coming. “Over two thousand years ago our ancestors did not live here but in a place far, far away which was part of a mighty empire and in that empire the words of the sun were beginning to spread. One night there were lots of bright lights in the sky and when the ancestors woke up the stars were strange and a stranger sun rose the next morning. In the days and years that followed the ancestors rebuilt their empire on this new world Terra Nova and gradually forgot about the words of the sun and Terra Prima but not completely, although the tales are now banned and repeating them is punishable by death.”
Reynolds tells the slaves that he wants to meet Kirquios, the First Citizen of the Empire, suspecting he is Captain Kirk of the Enterprise. Flavius offers to help and leads Reynolds to the capital city. The landing team puts on slaves' uniforms and tries to sneak into the city.
They are captured and placed into slave pens. After a failed escape attempt, they are brought before Kirquios and the Proconsul Constantius Vespasianus (guest star Anthony Bate), who invites the landing team to sit and talk in private. Kirquios acknowledges that he is Captain Kirk. When he beamed down he met Constantius Vespasianus, who demanded the planet's culture not be divulged to the Commonwealth, for fear of cultural "contamination." Kirk decided to stay, putting his crewmen into the gladiatorial pits, where they would certainly be killed. Kirk informs Reynolds that the Endeavour crew must also abandon their ship and integrate into Terra Nova's culture.
Reynolds refuses Kirk's demands and instead informs Decker that although the landing party is in trouble no rescue attempt is needed.
Holmes and Fynely are taken back to the slave pens while Reynolds is taken to face a televised execution.
Meanwhile, Scott works on a way to disrupt power and communications on the planet while obeying the General Order on not interfering with a planet's society. Blacking out the city just before Reynold's execution, Reynolds frees Holmes and Fynely but is soon captured again. Kirk signals the Endeavour to have Reynolds and party beamed to the Endeavour. Before he can complete the message, Constantius fatally stabs him for his treachery. Scott understands enough of the message and the landing party dematerializes just as they face a hail of machine gun fire.
Back on the ship, Holmes expresses to Decker and Reynolds his joy at seeing Christianity for such must be the words of the SON (not sun) survive. However they all, including Spock, are very worried by the “Tales of the Ancestors” as no records remain of the bright lights in the sky which must have occurred in about 300AD as Terra Nova’s year is not much different from Earth’s.