Lady Mary Sharma (Shelley Conn) is hoping to find a husband for Edwina (and Kate if she can manage), but she doesn't know that Kate has struck up a deal with her parents. It turns out that when Mary Sheffield ran off and got married to a lowly man, her parents disowned her for disgracing the family name. Her husband already had a daughter at the time — Kate — and when he died, Mary kept her as her own to raise alongside Edwina.
In an effort to help her family financially, Kate reaches out to the Sheffields, but they'll only help if Edwina marries someone with status, repairing the family name. When Mary finds out, she's cross with Kate, but grateful that she tried to help. She supports both her daughters — Edwina with choosing not to marry Anthony and Kate taking her place — and is content in the end with how it all played out.