In the waning days of World War II, dying Japanese fighter pilot Minamoto Ichiro joins a kamikaze flight with plans to die honorably by sinking an American warship. At the last moment, however, Ichiro is plucked from his plane by Hachiman, the Japanese god of war. It seems Hachiman needs Ichiro to save the universe.
Ichiro, now a samurai, finds himself in a parallel Japan-Nihon-where magic is real and Europeans have not yet arrived. He soon learns of Lord Taira, a warlord in league with dark forces. Taira has already stolen two of Nihon's sacred icons, the sacred jewel and sacred mirror The warlord now only needs the sacred sword, the legendary Kusinagi, the Grass-Mower, in order to control the universe. But sword is in Ichiro's hands, as only a member of the powerful Minamoto clan can wield the sword safely.
With the aid of a female ninja named Shizuka and Yukio, a naive young Buddhist monk, Ichiro must battle a series of evil forces, including dragons, undead warriors, river demons, a giant spider and a Dutch vampire sea captain in order to rescue the imprisoned young emperor.
But rescuing the emperor is not enough. Ichiro soon realizes the only way to save the universe is to reach the Bridge of Heaven, located on the island of Hokkaido, the home of the barbarian Ainu. Only then can he hope to bring the sacred sword, the sacred mirror, and the sacred jewel together to restore the Emperor's power and divine status. Assuming, of course, that he can defeat Taira's naval forces and somehow close the demonic gateway through which the forces of chaos might escape to overwhelm everything. That, however, will require Ichiro to enter Yomi, the very domain of Death itself...
