Metropolis is a futuristic city where humans and robots coexist. But robots are discriminated against, and many residents are unemployed and living in poverty, blaming robots for taking their jobs.
The Duke of Red, the underground ruler of the Metropolis, oversaw the completion of the giant skyscraper Jaegurat, claiming that Jaegurat would allow humanity to further expand its power on Earth. A robot sabotages Jaegurat's opening ceremony, and is then killed by Locke, the head of the Marduk Party's Anti-Machine People's Corps. Private investigator Shunsaku and his nephew Kenichi travel to the Metropolis to arrest mad scientist Dr. Lawton.
The Duke of Red secretly hires Dr. Laughton to build the advanced robot Dima, ready to make her ruler and operate Jaegurat's weapons. The Duke's adopted son, Locke, kills Dr. Lawton and sets fire to the laboratory in order to prevent Tima from finishing.
After detective Shunsaku finds Dr. Lawton dying, Dr. Lawton hands him a notebook. Meanwhile, Kenichi finds Tima in the lab, and they fall into the sewer. Kenichi and Tima accidentally encounter Locke. In order to escape from Locke's pursuit, Kenichi and Tima know Atlas, a bottom resident. Atlas plans to initiate a revolution, while the Metropolitan President and Mayor attempt to overthrow Duke Red's control. However, General Qusay, the President's top military commander, rebelled and killed the President. The Duke of Red strengthened his vigilance, suppressed the revolution, and the revolutionary leader Atlas was killed. After the failed uprising, Kenichi was arrested by the Duke, and Tima was brought back by Duke Red. Locke was removed as head of the Anti-Machine Popular Corps.
Locke induces Dima to leave the room, but is then attacked by detective Junsaku, who rescues Dima. Afterwards, Duke Red finds the whereabouts of the detective and Tima. The Duke tells Tima that she is a "superhuman" destined to rule the world. However, when Locke, disguised as a maid, shoots Tima, Tima's body exposes the circuit board, letting her know her true identity.
Realizing she was a robot, Tima took the throne and merged with Jaegurat, after which she ordered a nuclear attack on humans in retaliation. The robot began to attack Duke Red, and Locke did not want his father to die at the hands of the robot, so he pressed the stop button of the Jaegurat Building, and the Jaegurat Building began to be destroyed. After Tima loses her memory, she tries to kill Kenichi. After that, Tima replied to the memory and asked Kenichi: "Who am I?", and finally Tima fell from the tower.
The next morning, Kenichi encounters a group of robots who find some of Tima's parts. Shunsaku and Kenichi stay behind to rebuild the city because Kenichi wants to create a city where humans and robots can live in peace.
