The Clue of the Black Keys by Carolyn Keene
I was such a huge Nancy Drew fan when I was a kid. I have all my old books and a friend of mine picks up ones I’m missing when she runs into them at book sales. She recently gave me The Clue of the Black Keys which I hadn’t read as a kid. Of course, all Nancy Drew’s are essentially the same (I hear she’s been modernized in more recent times but these are the old ones). The plots are so full of happy coincidences. No set of criminals ever managed to drop more clues than her advesaries. But I can see why I enjoyed them so much. They just keep moving on and in such a comfortingly predictable way. Nancy and her friends never change.