Puzzle

She was orphaned and her uncle didn't seem interested in her. The people of St. Francis Academy were slowly becoming her new family over the course of the few years she was there. She was growing more aware of it being where she belonged, which paved the way for the surprising ending.

Marble Ann was the daughter of Mary's guardian, Uncle George, and her cousin. Marble Ann caught the mumps and I believe Mary stayed with her since she already had them and Uncle George hadn't.