Island of Exiles by I J Parker

A new Sugarwara Akitada novel! It is good.

I was initially skeptical, as the setup is that he has to disguise himself as a convict to infiltrate an island penal colony and solve a mystery there. Now, Parker hasn't written enough books that she has any justification to be running out of ideas. Also, it's hard to see why any of the characters thought it was a good idea. On the one hand, the mystery involves some important political exiles. On the other hand, disguised as a convict, Akitada has exactly none of his authority as an official and is forced into unlikely sneaking around.

In any case, once things get properly underway, the story is as good as any of the others.