This was published in 1987, one of her early books, and in the first few chapters, you can see her setting up the story structure better than you can see the story.
There is a planetary system where the people are on the moons and have been divided into Kinships with rigid code (behavior). There are three primary characters -- all women -- and all outside the Kinships. One is an off-world pilot, one has purposely separated herself from her Kinship, and one is a mediator from off-world hired to a Kinship to be their primary Medium (something like a mediator within code).
There is an ongoing increasing anger between the two major Kinships which eventually turns to feud and devastation. Our three women are parts of the solution.
I like Melissa's work, but unless you're a completist, you probably don't need to read this one. I must say that the cover image is not only interesting and accurate to a scene in the book, it's a scene that occurs before the big spoiler.