From Meisaku Translations:

Lady Rin! is the sequel of the beloved Lady!! At more than 20 years after the completion of Lady!! Hanabusa sensei retakes the plot. Now Sarah and Arthur are married and Rin lives with them at the Marble Mansion, while the duke, Aunt Magdalene and Charles live in the Woburn castle. Rin has been formally presented and is now a member of England’s high society. She dreams to participate someday in the horse-riding Olympics at Victoria’s side. Well she also has some dreams that concern Edward. As ever her life is a bit complicated. Some new character appear several handsome guys that kind of fall for Rin and also some splendid girls who are wooing after Arthur and Edward. On the top of everything, a great aunt of Arthur and Edward comes from America and she dislikes Rin because of her origins.

Will Rin succeed in becoming a gentle, strong and beautiful lady?