Our story begins when Ryu Hayabusa journeys to America to honor his father's will. While he is away, the barrier between the human and the demon worlds suddenly shatters, unleashing a terrifying army upon the Hayabusa Village, which now faces an unprecedented threat in Ryu's absence.

To stand against this new threat, Kenji Mozu, a young ninja from the Hayabusa Village, rises to the challenge! Trained by Ryu, he fights fiercely but soon finds himself in desperate straits. Forced to tap into forbidden power, Kenji sets aside centuries of animosity and forms an alliance with the sinister Black Spider Clan, convinced that combining their souls and skills is the only way to protect the world out of the Demon Lord's grasp!