In the short story The Shadow on the Glass, Mrs Iris Staverton is a noted sportswoman and traveller who had written a book about her adventures. She had once made a trip into the interior of Africa with big game hunters Richard Scott and Major John Porter.
Mrs Staverton is rumoured to have had a relationship with Richard Scott. For this reason, Lady Cynthia Drage thought that it was extremely unwise for the the Unkertons to invite Scott, his wife Moira and Mrs Staverton all to be guests at the same house party at Greenway's House. What transpires during the house party involving these three and others forms the main plot of the story.
Lady Cynthia Drage described Mrs Staverton as "a dangerous woman". Looking at her, Mr Satterthwaite had to agree. She is described as very fair, with deep blue eyes "not the traditional colouring of the siren" and "a face almost haggard in repose." "A woman with a slowdragging voice and a sudden dazzling smile." Wherever she goes she inevitably becomes the centre of the group.