A girl at the party mentioned an adoptive girl named Jodine Armstrong. Nancy has a hunch. Jodine sounds SO much like Joanie! Um, whatever, They visit Mrs. Armstrong. Jodine, aka "Jody", isn't around, but they don't give up. What if "Jodine Armstrong" is an alias? Something must be done!
The girls also keep exploring the castle, but this time Ned and crew comes to
Well, long story short, the head of the operation, Peter Suggs, confesses that he and some other men and a woman were working to steal Joanie Hornton's estate. Oh, and Jody Armstrong is Joanie Hornton. The person who sent Nancy the moonstone for good luck is her Joanie's Aunt Elaine. Nancy met her once, via her Aunt Eloise, and thought she (Elaine) was nice. But the woman inadvertently got a really sh1tty husband and it took a long time for her to get out of the mess.
All is well, until #41, The Clue of the Whistling Bagpipes.