The best episode written by Peter S. Beagle is "Sarek", rated 7.3/10 from 38 user votes. It was "directed by Les Landau". "Sarek" aired on 5/14/1990 and is rated 0.5 point(s) higher than their second highest rated, "Whale of a Tale".
Stardate: 43917.4. Spock's Vulcan father, Sarek, boards the Enterprise to negotiate political relations with the Legaran. However, Sarek has contract Bendii syndrome, which causes a Vulcan to gradually lose control, and become overpowered with emotions.
Director: Les Landau
Writer: Peter S. Beagle
Ariel finds an abanded baby whale, and decides to take care of it and be it's Mother. She names him Spot, but when Spot causes mass destruction around the kingdom Ariel decides to teach it how to survive in the wild.
Director: N/A
Writer: Peter S. Beagle