In San Francisco in the 1850s, a city where gold fever has left shipowners short-handed, Bat Morgan, a sailor come ashore is robbed and nearly shanghaied aboard another ship. Managing to escape, he sticks around town to pay back those responsible and then to take a cut in the action in the vice district. Organizing the various gambling houses into a consolidated enterprise in alliance with a corrupt city boss, Jim Dailey, he comes into conflict with a crusading newspaper, run by Jean Barrat, the daughter of the late murdered publisher, and Charles Ford, the idealistic editor. Loyal to his friends, even when they are on the other side, Bat Morgan protects the editor, when Jim Dailey orders him eliminated. He also falls in love with Jean, but his way of life and lack of any morality beyond looking out for number one make a permanent relationship all but impossible. Riled at a judge's snub, he determines to bring his Barbary Coast crowd to the opening night at the Opera House, which the Judge has opened as an alternative place of amusement to the gambling dens. A gambler, Paul Morra, shoulders his way into the judge's box and on a flimsy excuse, murders him. The outrage provokes a public outcry, and when Morra is arrested and jailed and a lynch mob gathers, crying for his blood, Bat arranges his release, not so much because he likes him as because he owes him a debt of gratitude for having started him on the upward rise. Soon after, Ford is murdered by Jim Dailey in a bar-room fight. Jean blames Bat, holding him responsible for all the evil done by those who work with him. A vigilance movement sets out to clean upthe town, rounding up Morra and Dailey, and hanging them both. When the lowlife of the Barbary Coast determine to pay it back by wrecking the press and burning the city, Bat Morgan convinces them to do otherwise. Trying to keep them from fighting back as the vigilantes come to destroy the Coast, he is shot in the back by one of the underworld forces and captured by the vigilantes. Jean Barrat saves him from hanging, and he is permitted to go free, on her parole.
