Synopsis
Teppei heads to a scientific conference to reunite with his older brother Kotaro Takamiya, having trained for eleven years under a mysterious woman named Karen. However, his plans for a family reunion are thwarted when a woman named Aramis kills everyone at the conference and kidnaps Kotaro. While on his way to rescue his brother, Teppei encounters a broken mechanical horse called B't X, which revives thanks to Teppei's blood and becomes his ally in saving Kotaro from the enigmatic Machine Empire.