A model is dead, and the police in the person of Inspector Ballard Berkeley have several likely suspects, but no proof that will convince a jury. The prime suspect looks to be painter John Bailey, who used to be engaged to her. He was subject to fits of jealousy and blackouts. I'm fact, he thinks he might have killed her. The ladies, sculptor Hy Hazell, Mary Germaine, and Sarah Lawson, are sympathetic to him. Fat Martin, who works at a club where the artists and models congregate, is a creepy possibility. And so on.
It's put together very well, both as a mystery and a story about the neurotics in the art world. One thing that helps is the darkness of the print. I am not sure if that was a deliberate choice to reflect the title, or simply a matter of the print, but it adds to the murkiness of the movie's story.