Re-reading an old favorite. This has almost all of the elements of a perfect Ruth M. Arthur book; a mystery, a troubled adolescent protagonist in search of her own authentic life, a scary old witch, a hidden treasure (not to mention a hidden garden), a love interest, and secrets piled upon secrets. The plot is deeply satisfying and the resolution on all fronts delicious. It's interesting how many plot elements Arthur recycled time after time- and how fresh they seemed to be in her hands.