Star trek: Faces of Fire

En route to Alpha Malurian Six to settle a dispute between two religions, the U.S.S Enterprise first stopped to do a routine check on the progress of a terraforming colony on Beta Canzandia Three colony, whose inhabitants include Caro and David Marcus.
While Spock is left behind at the terraforming colony to continue his scientific studies, the rest of the crew heads to Alpha Malurian Six to find that the dispute has turned into war.
As Kirk, McCoy, and Scotty search for a solution to end the conflict, a ship piloted by a Klingon faction arrives at the terraforming colony to take control of the facility. Spock and David must defeat the Klingons when the Colonists are imprisoned or face certain death.

used, fair condition