Barbara Cartland 
Beyond the Stars [EPUB ebook] 

The handsome Earl of Ardwick is smarting from the pain of discovering that his fiancée, the spectacularly beautiful but social-climbing Heloise Brook, is forsaking him for a Duke when he is halted on the road by a nasty carriage accident.
There he finds beautiful young Lupita Lang and her six-year-old brother, Jerry, who are running away from home. After the recent death of their father, Jerry has now become the Earl of Langwood.
Realising that he used to know their father well, he then takes them to the safety of his Grosvenor Square house where suddenly he sees Lupita in a new light.
With her fair hair and blue eyes she is the most beautiful girl he had ever seen and, as she tells him that their wicked Cousin Rufus is bent on murdering young Jerry in order to inherit his title, a cunning idea then comes to the Earl, a way to protect the young siblings from their grasping cousin and also to wreak revenge on the equally title-hungry Heloise.
After Lupita next appears on his arm dressed up as Cleopatra at the famed Devonshire House Fancy Dress Ball, to Heloise’s fury the Earl finds Lupita’s innocent allure increasingly impossible to resist and, although she does not know it, her heart is already his.
But surely their love is lost before it has any chance with Cousin Rufus still determined to end his young cousins’ lives and seize the title and estate that he so desperately covets.