The Black Bag [by Louis Joseph Vance]

Mr. Philip Kirkwood, a not so successful painter, receives a visitor from his home town in America, who wants him to do him 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 expects to 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 must be a mystery attached. He decides to protect the girl.

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The Black Bag [by Louis Joseph Vance]