The Covenant of the Crown

Summary
From the back cover: An Enterprise shuttle is forced to crash land in a violent storm on the barren planet Sigma 1212. Spock, McCoy, and Kailyn, the beautiful heir to the Shaddan throne, survive in the near disaster.

Now, pursued by primitive hunters and a band of Klingon scouts, they must reach the mountain where the fabulous dynastic crown is hidden. With the help of Spock and McCoy, and her own fantastic mental powers, Kailyn must prove that she alone is the true heir to the throne.

If they fail, they will open the door for Klingon takeover of the whole quadrant - and the galaxy's hope to live long and prosper will fall in the shadow of a cruel tyranny.