Below decks on an ocean liner one hour out from its New York port, the firemen who power the ship by stoking coal drink, curse, and sing, creating a defiant uproar. The strongest and most respected of the group is Robert Smith, known as Yank, who takes pride in his strength and in the ability of the crew to power the engines. Yank’s shipmate Paddy, a wizened old Irishman, yearns for the days of the graceful clipper ships that plowed the Atlantic silently, when men were in harmony with nature. A socialist agitator named Long curses the capitalist class that has forced the crew to slave for wages in the bowels of the ship. Rejecting these views, Yank sees himself as the mover of the world.

On the ship’s promenade deck, rich young heiress Mildred Douglas and her overly rouged aunt recline in deck chairs. Mildred is the spoiled daughter of the steel-company president who chairs the liner’s board of directors. She wants to visit the ship’s stokehold to discover how the other half lives. Mildred’s aunt considers her interest in social service to be superficial and calls her a poseur. Mildred responds that she is sincere and wants to help those in need. Dressed in white, she insists that the ship’s officers take her below. When they reveal to Mildred the stokers in all their brutality, she is repulsed and frightened. At the sight of Yank, who is caught unaware by her presence, she cries out and faints. Later, Paddy remarks to Yank that the young woman looked as though she had seen a hairy ape. His identity and sense of belonging shattered, Yank vows to get even.

When the ship returns to New York, Long attempts to channel Yank’s hurt and fury against Mildred into rage against the ruling class. He shows Yank goods displayed in Fifth Avenue store windows, goods that will never be available to Yank, and he rails against the callous behavior of rich Sunday churchgoers. Unmoved at first, Yank becomes excited when he sees a coat made of monkey fur in a store window. It reminds him of Paddy’s comment. He becomes further irritated when the men and women of Fifth Avenue ignore his hostile advances and seem not to see him. Maddened by the crowd’s delighted cries at the sight of the monkey-fur coat, he tries in vain to pull up a lamppost to use as a club. Not even punching a gentleman in the face brings him recognition: His arrest occurs only after the gentleman’s accusation that Yank caused him to miss his bus.

Jailed for thirty days on Blackwell’s Island, Yank at first thinks he might be caged at the zoo. His fellow inmates, learning of Yank’s anger at Mildred, suggest that he can gain revenge by joining the Wobblies, the Industrial Workers of the World (IWW). According to newspaper stories, the IWW is a tough gang whose members dynamite buildings and seek to destroy American society. Yank realizes that Mildred’s father, the president of the Steel Trust, made the steel of the ship where he thought he belonged, as well as the steel that imprisons him in jail.

Once he is freed from jail, Yank goes to the IWW office, believing that with his strength and purpose he will be useful to the group in its supposedly violent activities. After being welcomed by the IWW secretary, Yank assures the men that he is a regular guy and indicated that he is “wise” to them. The secretary tries to explain to him that the IWW’s activities are legal and aboveboard. Yank...