In a highly advanced city of the near future, where humanoid robot technology is extremely sophisticated, the boy detective Kenichi becomes entangled in a conflict. The powerful politician Duke Red, devastated by his child's death, commissions a scientist to build a substitute: an exquisitely beautiful, sex-changing robot child named Mitchy. Note that this original 1949 manga provides only a portion of the plot for the recent Metropolis movie, and does not include Rock, whose role in the film was adapted from Phoenix, Nextworld, and other Tezuka manga.