Remember the scene near the beginning of "Star Trek II: The Wrath of Khan" where Admiral Kirk is mildly depressed and Dr. McCoy encourages him to get back his command of the Enterprise? That scene is recounted at the beginning of this engaging little story, where it gets McCoy thinking of an emotional crisis of his own way back when.
The bulk of this novella (probably about a hundred pages long if it ever appeared in print form) describes an early adventure of McCoy's on the remote planet of Capella IV, where McCoy and his medical colleagues study and interact with a primitive humanoid species, with the aim of trying to secure permission from the tribe's leaders for the Federation to mine a needed ore from the planet. The Prime Directive, politics, and a "needs of the many versus the needs of the few" situation all conspire to create a personal and professional crisis for McCoy, which he recounts to Mr. Spock years later after his meeting with the depressed Kirk.
As I said, this is an engaging little story, with interesting details about the alien race, decent banter and interactions among the Starfleet personnel, and even some saucy humor involving the alien race's mating rituals. The story's conclusion depends a little on being familiar with how things eventually worked out for Kirk in "Star Trek II", but I suspect that 99 percent of the people who purchase this story will already be up to speed on that.
In the end, Michael A. Martin has written a crisp, entertaining novella that is true to the characters we know, and well worth the modest price being asked.