In dire need of a more serious tone after the humorous but somewhat inconsistent Shore Leave, Star Trek returns to its tradition of tackling deeper themes from a sci-fi point of view, focusing in particular on Spock's interactions with the rest of the Enterprise crew.<br /><br />This time, Kirk's mission is to bring medical supplies to the inhabitants of Markus III as quickly as possible, and his superiors keep reminding him of that priority. However, his priorities change when the smaller vessel Galileo, containing Spock and six other men (hence the episode's title), lands on a hostile planet and requires immediate assistance. With Kirk torn between duties, it's up to Spock to come up with a solution, but his adherence to logic doesn't sit well with some, most notably Boma (Don Marshall), whose behavior comes close to bigotry.<br /><br />Racism and the implications of being in charge: those are the two key topics of this suspenseful Trek tale, and both are handled admirably thanks to the writers' focus on the tense relationship between the half-alien Spock and the entirely "human" crew under his command, while William Shatner is elegantly sidelined as far as the drama is concerned. Then again, Spock has always been the more interesting of the two leads, and Nimoy relishes every opportunity he gets to show a little of the Vulcan scientist's complex, enthralling (and, a rarity for science-fiction shows, Emmy-nominated) personality. In addition, no need to worry about excessive darkness: the deft humor returns in the final scene, which contains one of the absolute best exchanges between Kirk and Spock. Sci-fi doesn't get much more fun than this.