The story takes place in a city resembling Italy, known as Belmonte, with the technology levels resembling levels in the late 19th century. In this city there are human-sized mechanical dolls known as "Automata" who serve the people of the city.

The protagonist, Romeo, is a taxi driver who was originally involved in a organization known as the "Orma Rossa." He finds an automata in the shape of a young woman, who appears to have amnesia. He names her Anna, they start living together. However, sometime later, the Orma Rossa begin to catch up to Romeo, and an organization composed of automata also appears; thus, Romeo must fight to protect his current life.