The Beanstalk Murder - a middle grade fantasy novel by P. G. Bell - involves a young witch in training, her archenemy, the kingdom of giants, and a huge murder mystery
Anwen sedge, a young meadow witch apprentice, lives in a rural village that hasn't seen giants since the Great Beanstalk War. So it's quite a surprise when one drops from the sky and squishes the village flat. It's an even bigger surprise when Anwen discovers...