Peter Dawes continues the search for Jack Rhodes by taking stagecoach and steamboat to San Francisco where Rhodes was shanghaied. Even before Dawes returns to San Francisco, Rhodes experiences a shipwreck and rescue by a very literate and murderous captain who commands the Arkadia, bound for San Francisco with a cargo of opium for Oyster Mike, known as an oyster pirate but in reality the man who controls the vice payoffs in the Barbary Coast. One danger that Dawes is unaware of is that the brother of the half-breed he killed in Susanville has returned to the frontier town. When Tug finds out that Dawes killed his brother he sets out for revenge. Dawes uses his skills as a confidential investigator to ferret out information about what happened to Jack Rhodes. In the meantime he is approached by various other San Franciscans, including the notorious Captain Breen, to embark on investigations that are intertwined with his search for Rhodes. Dawes ultimately finds Rhodes and helps him to escape the Arkadia. As Dawes, Rhodes and a policeman enter the New Bella Union, owned by an acquaintance of Rhodes, the Arkadia's crew, Oyster Mike and his men, and Captain Breen converge on the New Bella Union. Tug is gambling at one of the tables in the New Bella Union, but he is unaware that Dawes has entered the establishment.