Duncan and Gemma and little bones
This is the next-to-most-recent of the Duncan and Gemma mystery series. Truthfully, it is not the mystery that draws me back to the series, but the marvelous characters and their relationships. Ms Crombie must have had lots of fun with this weblike story-making. There must be at least half a dozen sub-plots in a fairly long book, each working itself out into the final resolution. Duncan, Gemma (who is nervous about it), and their two boys (also a dog, if I remember correctly--it's a very complicated plot) set off to celebrate Christmas with Duncan's family. Gemma has never met them, and wonders whether they will like her, whether they will be put off by the kind of relationship she has with their son, and just what is going to happen.
What does happen--surprise!--is the discovery of a tiny skeleton in the wall of a barn Duncan's sister is remodeling. Then Duncan meets an old comrade in the person of the law enforcement officer who takes on the case. Then Duncan's son gets involved with his rather unstable cousin, and...well, you get the picture. You have to keep track of many characters, all bungling their way to the final pages. In the midst of this semi-ordered chaos, and a couple more murders, the inner relationship of the two detectives becomes more available to the reader, and you are dying to get your hands on the next book.
The depiction of enclosing nature in the form of climate, season, tree and temperature are an added bonus in this series.