“One of Our Planets is Missing”
Written by Marc Daniels
Directed by Hal Sutherland
Animated Season 1, Episode 3
Production episode 22007
Original air date: September 22, 1973
Captain’s log. The Enterprise is investigating a cosmic cloud that is entering the galaxy and is proximate to Mantilles, the inhabited Federation planet that’s closest to the edge of the galaxy. The cloud is huge, more than 800,000 kilometers wide, made of both matter and energy. It engulfs one of the planets in the system and destroys it, then changes course in order to head for Mantilles.
On McCoy’s recommendation, Kirk has Uhura contact Bob Wesley, the governor of Mantilles, to warn him and have him start evacuating the population, even though they’ve only got four hours before the cloud hits Mantilles. Wesley can only evacuate the children on the planet in time.