Louis Joseph Vance (1879–1933) was an American author and novelist, mostly known for short stories, and popular novels that brought him universe recognition especially for his character "Michael Lanyard", also known as "The Lone Wolf", that was featured in eight books and 24 films between 1914 and 1949, and also appeared in radio and television series. “The Black Bag” by Louis Joseph Vance is a story of a detective type with a rapidly-moving narration. The main character is Mr. Philip Kirkwood who is not so successful painter, receives a visitor from his home town in America, who wants him to do an unspecified favor, but Kirkwood doesn''t trust him and sends him away. That night, he sees the stranger dine with his beautiful daughter. In order to protect the girl, the stranger confesses to Kirkwood, that he will be arrested upon leaving the restaurant. Kirkwood agrees to take care of the girl, but when he brings her home, he knows that she is in danger and that there is a mystery attached. What did he decide?