Fred M White 
The Midnight Guest [EPUB ebook] 

A HANSOM pulled up in front of 799, Park Lane, and a slim figure of a woman, dressed in deep mourning, ran up the broad flight of marble steps leading to the house. Her features were closely concealed by a thick veil, so that the footman who answered the ring could make nothing of the visitor. Her voice was absolutely steady as she asked to see Lord Ravenspur at once.
‘That is impossible, madam, ‘ the footman protested; ‘his lordship is not yet down, and besides—’
‘There is no ‘besides’ about it, ‘ the visitor said, imperiously. ‘It is a matter of life and death.’