In 1999 a mysterious object crashes into the desert and a mysterious creature, Darc Seed appears. Using magnetic powers, he soon turns the people of the United States into zombies and exerts influence over various weapons and objects. Among the weapons Darc Seed claims is the legendary samurai sword, Shura. When the great head of the samurai, Namakubi hears about this, he sets out for the United States to defeat Darc Seed and reclaim the sword.
What makes this so unusual however is that "great head of the samurai" is to be taken literally and Namakubi therefore is a giant disembodied head. His main weapon is the ability to shoot projectiles from his eyes and bombs from his mouth which he fires at various enemies, objects and buildings. Furthermore, should a zombie hostage fall out a window he can rescue them to slowly power up his attacks.