Mildred Douglas and her Aunt lounge on the ship's promenade deck. Basking in the bright sunlight, Mildred remarks at the beauty of the black plumes of smoke wafting into the blue sky. Unfettered and relaxed, Mildred and her Aunt sit painfully disconnected from the workings of the ship, the world of Yank and the other firemen below. Mildred and her Aunt are "artificial characters," solely bred from and pampered by aristocratic and monetary pleasures. Mildred, the daughter of a steel tycoon, is aware of her disconnection from the poorer classes. She attempts regain some connection to and understanding of the "other half" by studying sociology and doing various service projects.
Mildred currently awaits the Second Engineer who will take her on a tour of the stokehole so she can investigate the state the workers on the ship. As she waits, Mildred and her Aunt quibble about Mildred's desire to help the poor. Mildred abhors her Aunt's apathy. Mildred's Aunt kindly tells her niece she is a "ghoul," that Mildred's work with the poor will only make them feel poorer. Mildred's Aunt has no idea why Mildred would desire to work with such people, as she loathes "deformity." Mildred describes her dispassionate Aunt as a "cold pork pudding against a background of linoleum." Mildred not only wishes to understand and help the poor, but she seeks to find purpose in life. Mildred expresses to her Aunt that she feels like a "waste product" of her family's steel business. She has reaped the rewards, but has no taste for the vigor and fight that brought them. Mildred's Aunt thinks Mildred's service projects are simply fanciful indulgences, a trendy suit of sincerity and humbleness that will be short-lived. Mildred compares herself to a leopard who complains of his spots. Mildred is trapped in an identity with spots she cannot "scratch off." The first engineer interrupts Mildred and her Aunt to escort Mildred to the stokehole. He asks Mildred if she would like to change out of her bright white dress before descending. Mildred replies that she has fifty dresses just like it and she will simply toss it into the sea when she returns. As Mildred follows after the engineer to the lower decks her Aunt calls after her, "poser!" Laughing, without pause, Mildred fires, "Old Hag!"
Scene Three opens in the stokehole where Yank and the Firemen are busy shoveling fire into the ship's furnace. The men shovel in a rhythmic motion, swinging shovels of coal from the pile into the furnace doors. The sound of steel doors slamming, the clank of the shovels against the engine and the raging fire is deafening. The men stop for a short break. Paddy remarks that his back is broken and Yank tells him he is being weak. Yank rallies the other men to keep working and enthusiastically cheers them on. Paddy once again interjects that his back is broken. From the dark region above a whistle sounds instructing the men to keep going. Yank furiously shakes his fist at the whistle blower and shouts that he is the one to decide when people move. In a fit he starts to work once again with the other men. Meanwhile, Mildred has entered the stokehole with the Engineer. While Yank keeps shoveling, the other men turn to stare at the ghostly Mildred, in stark white against the coal-blackened room. As the workers have stopped to stare, the whistle blows once again. Yank yells threats up to the whistle-blower and brandishes his shovel. Suddenly he becomes aware that the other men have stopped working and swings around violently to see Mildred. Mildred, pale and about to faint, is helped by the engineers. Before she is carried away she whimpers, "Take me away! Oh, the filthy beast!" Yank roars, "God damn yuh!"
The progression of and stark contrast between Scene One to Scene Three exemplify the wide gulf between the world of the worker and the world of the passenger on the Ocean Liner. The audience experiences these two worlds, representative of upper and lower social classes, through Mildred Douglas and Yank—the epitome of the worker and the aristocratic and over-privledged child. The audience is taken from the brightly lit promenade deck where Mildred and her Aunt bask in the sun to the stokehole where "one hanging electric bulb shed just enough light through the murky air laden with coal dust to pile up masses of shadows everywhere." In contrast, the promenade deck where Mildred and her Aunt sit is "beautiful sunshine in a great flood, the fresh sea wind blowing across it."
There are also enormous physical differences between Mildred and the firemen. She is skinny, pale and wears white. The firemen are characteristically blackened by coal dust, dirty and muscular. O'Neill describes Mildred's expression as "looking as if the vitality of her stock had been sapped before she was conceived, the expression not of its life energy but merely of the artificialities that energy had won for itself in the spending." The Firemen are perhaps as "natural" or "in-human" imaginable, constantly compared with Neanderthals and animals, described as a "chained gorillas."
Mildred and Yank, artificial and animal, are both transposed onto canvasses that contrast their character. Mildred (the unnatural) is surrounded by powerful ocean, Yank (the animal) is caged in steel. It would seem that neither character belongs in his or her environment. This is not to suggest that Yank should live in a jungle and Mildred should sit in a plastic box, but it shows that both of these characters actively struggle with their environmental and class boundaries. Yank yearns to become steel and Mildred desires to learn what is natural. Their attempts to do so drive the action of the play.
In Scene Two, Mildred attempts to leave her environment and visit the men in the stokehole. Yank leaves his boundaries as he visits New York City later in the play. Both characters meet disaster when they try to cross their social boundaries. When Mildred goes to visit the stokehole where Yank and the Men are working she is overwhelmed and faints. When Yank visits 5th Avenue he is incapable of communicating with or existing within "civilized" society and retreats to the zoo. Both characters are stuck in worlds they wish to escape, but are ill equipped physically and emotionally to do so.
Thus, both Mildred and Yank attempt to scratch off their "spots." Like the leopard Mildred describes to her Aunt, Mildred and Yank are unsatisfied with the life, bodies and society they have been born into, but are powerless to change them. Both the aristocracy and the lower classes instruct Mildred and Yank to "Purr, scratch, tear, kill gorge yourself and be happy—only stay in the jungle where your spots are camouflage in a cage they make you conspicuous." O'Neill develops the theme of entrapment through characters that exist within extremely different social strata. The mutual discontent and helplessness shared by Yank and Mildred is not only imposed by the greater societal structure. Their discontentment also stems from a restless ignorance of their societal and natural other—Yanks lack of knowledge of Mildred and Mildred's ignorance of Yank.