A samurai solves mysteries! Well, not quite. Sugawara Akitada is a nobleman and courtier in eleventh century Japan, and he solves mysteries. He's trained as a lawyer, but also knows all the other skills of the upper classes.
In this novel (midway in the series) he gets sent with his retainers and family as governor of a frontier northern province (the war with the Ainu people is ongoing at the time). A murder on the day he arrives leads to various sinister plots.
It's a really good read, with lots of interesting historical detail (in this case, about a part of Japanese history I wasn't familiar with) and well-drawn characters.