Ma (Bobo Lewis) and Pa (George Hall) let a traveling salesman, Howard Filby (Soupy Sales), into their home during a terrible thunderstorm. He's permitted to spend the night, but must share a room on the second floor with their daughter, Lucy. Lucy has a beautiful voice, but Filby can only see her in silhouette through a bedsheet dividing their room. When he convinces Lucy to lower the sheet, she turns out to be just as beautiful he expected. But Lucy demands commitment from her lovers, and harbors a horrific secret.