In the Harley Quin short story The Sign in the Sky, Vivien Barnaby was the wife of Sir George Barnaby. Much younger than her elderly husband, she had married Sir George before she knew what she was doing or before she understood his miserly ways. She soon felt trapped in the marriage and deeply unhappy.
When she met Martin Wylde, a gentleman farmer and a neighbour, she saw in him a means of escape. Her servants thought she led him on, pretending to be interested in farming when what she wanted was to grab hold of him romantically. They pursued a relationship for a while but at some time, Martin's affections cooled and he became interested in another woman Sylvia Dale instead. Lady Barnaby would not give up and wrote Martin many letters, the last of which entreated him to come over to her house to talk things over.
It was under these circumstances that Lady Barnaby was found murdered in her house, shot in the head by a gun belonging to Martin. She was killed on Friday, September 13th. Martin's subsequent arrest, trial and conviction forms the preamble to the plot of the story.