Sherlock Holmes sets out to discover why a trio of murderous villains, including a dangerously attractive female, are desperate to obtain three unassuming and inexpensive little music boxes.

Paula's aunt, Alice Alquist, a famous entertainer, is murdered in her home. Paula, who lives with her aunt, finds the body. Police fail to find the killer, and Paula is sent away to school. Ten years later, Paula returns to London with her new husband. They take up residence in her aunt's house, which she has inherited. Paula is increasingly isolated by her husband but does come to the attention of an admirer of her aunt, Mr. Brian Cameron.