Billy Byrne is a mucker, a low class American born in Chicago's ghetto. He grows up a thief and a mugger. 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. When falsely accused of murder, Billy flees to San Francisco and is shanghaied aboard a ship. The ship's secret mission is to hijack a millionaire's daughter, Barbara Harding, for ransom. After a terrible storm, the ship is damaged and Billy rescues Barbara. He protects her from the jungle for weeks and they fall in love.
In The Return of a Mucker Billy goes back to his old Chicago haunts intending to clear his name. His time with Barbara imbued him with faith in the law and justice. However, he soon realizes that the system is more interested in finding someone guilty than in finding the guilty party. Awaiting the verdict, he reads that Barbara and Mallory are about to marry.
The Oakdale Affair features the Return of The Mucker sidekick, Bridge. In the home of Jonas Prim, president of an Oakdale bank, a thief makes off with a servant's clothing and valuables belonging to Prim's daughter Abigail. Escaping, the thief later encounters a group of hobos and is taken for one of them, the Oskaloosa Kid. Two of the hobos attempt to murder the newcomer for the loot, who shoots at one and flees.
Edgar Rice Burroughs (1875–1950) was an American writer best known for his creations of the jungle hero Tarzan and the heroic Mars adventurer John Carter, although he produced works in many genres.