Phyllis Allenby was the descendant of Reginald Allenby, a young English woman who lived in the care of her "aunt" (actually merely a close family friend), Carol Winthrop. She was all set to marry the handsome young Barry Lanfield when a series of grisly murders that occurred in the nearby park caused Phyllis to believe that she had fallen prey to the dreaded Allenby Curse and transformed into a werewolf nightly to commit the deeds.
Although she locked herself in her room (avoiding Barry in the process), she awoke each morning to discover her shoes muddy and her nightgown covered in blood, and was distressed to learn from the newspapers that a Scotland Yard detective named Latham and, even worse, a small child had been killed in the park by what the papers called the "She-Wolf." Phyllis became physically ill thinking that despite all her precautions she had killed those people.
Eventually, it was revealed that "Aunt" Carol was the one committing the murders in the guise of the She-Wolf, knowing that Phyllis believed in the stories about the Allenby Curse, hoping to drive her mad so that she would call off her marriage to Barry Lanfield, allowing Carol's own daughter Martha Winthrop to marry him. Carol tried to kill Phyllis in her bedroom, drugging her glass of milk to incapacitate her. Luckily, Phyllis was saved thanks to the timely arrival of Hannah, and was reunited with Barry. The two married as planned.