When I was about Fancy Nancy's age, I had a set of Holly Hobby rag dolls.
This is not one of my dolls. I don't remember what ultimate end my dolls came to, but I very distinctly remember the day I took them all to the neighbor's house to play, and her little brother CUT OFF ALL THEIR BRAIDS!
Scandal. Heartbreak. Actually, I think my mother was even more upset than I was, but, still! Raise your hand if you can instantly name a time when a younger sibling or playmate ruined your favorite truck/book/doll/toy. You just got mad at your little brother all over again, didn't you?
We can understand, then, Nancy's dismay when her little sister draws a skull-and-bones TATTOO on Marabelle! Yes, Marabelle, her very fancy doll who is with her in EVERY book! This is a tragedy beyond epic proportions. Nancy's mother tries to console her by taking them both (Nancy and Marabelle, of course - Jo-Jo is stuck at home) to a doll gala. While there, an even worse tragedy is narrowly averted, and Nancy discovers she is not the only older sibling of a 'handful'.