When last we left the crew of the star ship Enterprise, they were heading home following a skirmish with the despotic Khan. The unpleasant incident had cost the life of Mr. Spock (Leonard Nimoy)--or so it seemed. Admiral Kirk (William Shatner) is informed by Spock's father Sarek (Mark Lenard) that his son is being kept alive in the thoughts of one of the crew members. It now becomes necessary to search for Spock's body, so that flesh and soul can be rejoined on Vulcan. It turns out that Spock's spirit is residing within the mind of the Vulcan's longtime shipmate, "Bones" McCoy (DeForrest Kelley). Finding the body is another matter, since the Enterprise has been consigned to the trash heap and thus is out of Kirk's jurisdiction.
by Hal Erickson synopsis