This is number thirteen in the "Number One Ladies' Detective Agency" series. I have read all these books and they are great.
It's set in Gabarone, Botswana (a country in Africa), and features some of the most low-key but absorbing detective stories I've read.
I mean, it's not murder, mayhem and gore; it's human nature and real situations. You may feel it moves slowly, but the story will grab you if you give it the time.
I recommend starting with the first book though. (The No. 1 Ladies' Detective Agency)