The city of Metropolis is burdened by strict societal hierarchies and biases between humans and robots, resulting in increasing unrest and violence on a daily basis. Seeking to uncover the truth behind Dr. Laughton's alleged illegal trading of organs and violation of human rights, Japanese detective Shunsaku Ban and his nephew Kenichi arrive in Metropolis. Inside the doctor's lab, Kenichi encounters a woman with no memory of her past, and he vows to help her escape. Despite his efforts, Shunsaku pursues them as he delves into the seedy underbelly of the city, on a mission to find the enigmatic Duke Red, a mysterious figure with a hold on power. Meanwhile, Kenichi fights to protect the young woman from those who would capture her, unaware that Duke Red and his son are also after her, and their true motives are connected to her identity and the intense power struggle gripping Metropolis.