Well, there really wasn't a great mystery about the missing lion, but I guess that a very small child would find the story exciting - or maybe not.
I get the feeling that the children whose audience the author is aiming for, lived some time in Victoria times, as I've often found that a modern child has far more sophisticated tastes in reading than this story.
I think I'm probably biased, though, as I find these young Precious Ramotswe stories a little patronising to children, with too much over explanation, and a view of the world that feels very middle class to me.
I guess that these, too, will not be read by me again, now I've read them once - so there's just one more to go: The Great Cake Mystery.