A hijacking incident has occurred!! Genta and Yukimi are imprisoned in the forbidden area, Area 666, by the mastermind Azuma. The three Igarashi siblings go to the forbidden area to save their parents. Azuma, who stands in the way of the three siblings, transforms into Kamen Rider Daimon and decides the survival of mankind. At the same time, the mysterious scientist Gokai who appears in front of Genta and Yukimi reveals his purpose and pursues the Igarashi family. When the trap set leads to the greatest crisis approaching, the bond between the strongest family creates a miracle!