A factory worker is driven crazy by his job, meets an orphan girl, and tries to earn money so they can have a home.
The president (Allan Garcia) of Electro Steel watches factory workers on a screen and orders them to speed up. The Worker (Charlie Chaplin) tries to keep up, tightening bolts on an assembly line. The president is given a recorded sales pitch for an automated feeding machine. During lunch the machine is tried on the Worker, but it needs adjusting and makes a mess. The president says it's not practical. Extra speed takes the Worker into the huge factory machine. He chases a blonde secretary into the street and eyes the buttons on a woman's bust. The Worker dances in the factory, is chased, and taken to a hospital. Released, he picks up a red flag and is joined by a protest march; then he is arrested.
On the waterfront the Gamin (Paulette Godard) steals bananas for her motherless sisters and unemployed father. In jail the worker quarrels with his cell-mate, uses salt that is smuggled "nose powder," and captures escaping prisoners. The Gamin finds her father shot dead and runs away from juvenile officers. Radio reports the release of the heroic prisoner. The Worker asks to stay in jail but is given a letter of recommendation. He gets a job on the waterfront, launching a boat by removing a wedge. The Gamin steals bread and runs into the Worker, who says he took it; but she is arrested. He eats in a cafeteria and is arrested for not paying. He helps the Gamin escape from the police wagon. They smile and imagine being in a suburban home. The Worker gets a job as a night-watchman at a department store, and they roller-skate. The Gamin tries a robe and a double bed. On skates the Worker is shot at by burglars. Big Bull (Tiny Sandford) recognizes the Worker from the factory and says they are hungry. The Gamin wakes up at 6; but the Worker is found asleep at 9:30 and is arrested.
Ten days later he gets out and is greeted by the smiling Gamin, who shows him an old shack she calls paradise. At a meal he sees in the paper that a factory is opening. He works on machinery with a mechanic (Chester Conklin). Their tools are ground up, and his partner is caught in the machine. The Worker has to feed him lunch. The workers go out on strike; when a brick hits a policeman, the Worker is arrested again. The Gamin dances in the street and is hired to dance in a nightclub. She welcomes the Worker when he gets out of jail and gets him a job as a singing waiter. He tries to serve duck on a crowded dance floor. The Gamin writes lyrics on his cuff; but it flies off, and he makes up French words. The Gamin is picked up for vagrancy but escapes. On a country road she cries in despair, but the Worker tells her to smile, as Chaplin's song "Smile" is heard.
This prophetic satire of the machine age portrays the exploitation and dehumanization of workers followed by repression when they protest. While the capitalist class expects to be waited on, the unemployed suffer hunger. The Worker is even spied on electronically during a bathroom break and is told to get back to work.