Daughter of a detective, Ethel King takes up her father's career in order to avenge his death, as well as that of her fiancé, both brought down the same day by an assassin's bullet. King, like Miss Boston and Therese Arnaud, is an extraordinary woman, well ahead of her time. Although she practices a masculine profession, she is seductive and charming, moves comfortably in high society, and dresses elegantly. These characteristics hide her incisiveness, daring, strength, and accuracy with a gun. She solves cases involving murders, kidnappings, forgeries and extortions. She brings the guilty to justice, earns a satisfactory living and leads a comfortable life in Garden Street, Philadelphia.

There were only two women sleuths in French popular literature before the mid-20th century. The first, Miss Boston, was created by Antonin Reschal and appeared in 1908-1909. Jean Petithuguenin (1878-1939) wrote the second, Ethel King, shortly thereafter (1911-1914). This professor at the Faculty of Sciences was the official translator of the Nick Carter series. Ethel King ran for more than 100 bi-weekly issues in France, then was continued in Germany by other authors.