Christine Blakely has a strong desire to murder her husband, Richard, and she can't get the fantasies out of her mind. She's so tormented by these thoughts, that she reaches out to psychoanalyst Dr Campbell to help her. He tells her to go home and take some sedatives, and then later contacts Sherlock Holmes for his advice. Holmes is furious that the man has been so shockingly careless, and heads to the Blakely home right away. But will he make it in time?