B't X Teppei Takamiya is the caretaker of a farm located in Kamui Island, north of Japan. His older brother, Kotarō Takamiya, leaves to study robotics in Germany and becomes one of the most brilliant scientists in the world. Five years later, the two brothers reunite at a robotics convention in Mechatopia, China, where Kotarō is to announce his latest breakthrough in artificial intelligence. The convention goes awry when Kotarō is captured by the malevolent Machine Empire and taken to "The Area".