Billy Byrne is a low class American born in Chicago's ghetto. He grows up a thief and a mugger. "Billy was a mucker, a hoodlum, a gangster, a thug, a tough." He is not chivalrous nor kind, and has only meager ethics - never giving evidence against a friend or leaving someone behind. He chooses a life of robbery and violence, disrespecting those who work for a living. He has a deep hatred for wealthy society. He trains as a prizefighter but can not stop drinking. When falsely accused of murder, he flees to San Francisco and is shanghaied aboard a ship. Ironically, enforced sobriety, brutal ship's discipline and productive work improves him. The ship's secret mission is soon enacted - the hijacking of a specific yacht to take a millionaire's daughter, Barbara Harding, for ransom. Originally two stories, The Mucker begun in August 1913 and published by All-Story Weekly in October and November 1914; and The Return of the Mucker begun in January 1916 and published by All-Story Weekly in June and July 1916. The book version was first published by A. C. McClurg on 31 October 1921. From January 1922 to August 1939, Methuen (UK) published a version of The Return of the Mucker under the title The Man Without A Soul.

Billy Byrne squared his broad shoulders and filled his deep lungs with the familiar medium which is known as air in Chicago. He was standing upon the platform of a New York Central train that was pulling into the La Salle Street Station, and though the young man was far from happy something in the nature of content pervaded his being, for he was coming home. After something more than a year of world wandering and strange adventure Billy Byrne was coming back to the great West Side and Grand Avenue. Now there is not much upon either side or down the center of long and tortuous Grand Avenue to arouse enthusiasm, nor was Billy particularly enthusiastic about that more or less squalid thoroughfare. The thing that exalted Billy was the idea that he was coming back to \show them\. He had left under a cloud and with a reputation for genuine toughness and rowdyism that has seen few parallels even in the ungentle district of his birth and upbringing. A girl had changed him. She was as far removed from Billy's sphere as the stars themselves; but Billy had loved her and learned from her, and in trying to become more as he knew the men of her class were he had sloughed off much of the uncouthness that had always been a part of him, and all of the rowdyism. Billy Byrne was no longer the mucker.

Short From behind a low bush across the wide lawn a pair of eyes transferred to an alert brain these simple perceptions from which the brain deduced with Sherlockian accuracy and Raffleian purpose...