Kidnapped foster brothers Kôtarô Minami and Nobuhiko Akizuki were turned into cyborgs by the evil empire Golgom. Having managed to escape, Kôtarô transforms into Kamen Rider Black, dedicated to fighting Golgom, and searching for Nobuhiko.

Continuing the adventures of the "Kamen Rider" genre. Minami Kotaro is chosen by Golgom to be the Century King along with his best friend. Kotaro escapes and transforms into the 11th Kamen Rider, Kamen Rider Black. Unfortunately, his best friend never got away and slowly became "Shadowmoon." Kotaro battles Golgom and "Shadowmoon" for 51 in-your-face-action-packed episodes.—Hongou