The game follows the exploits of the powerful ninja Yaiba Kamikaze. Yaiba was once part of a clan that tested the abilities of its ninja by putting them up against a highly skilled member; in this case it was Yaiba they had to face. However, after growing weary of his work, Yaiba eventually decides to massacre his own clan and leave the survivors to their deaths. At one point he meets with the franchise mainstay Ryu Hayabusa and decides to challenge him, claiming that he is the weakest foe Yaiba has encountered thus far. During the battle he discovers otherwise as Ryu slices Yaiba's left arm and eye, killing him.
Later, Yaiba is discovered by a mysterious organization known as Forge Industries, led by Alrico del Gonzo, brings him back to life and restores his lost body parts with mechanized duplicates, thus turning him into a cyborg, with a female scientist named Miss Monday as his navigator. Yaiba learns that a zombie outbreak has begun and that Ryu has been searching for the source of the infection. He decides to work with the Forge Industries that resurrected him in order to exact his revenge against Ryu, agreeing to help put a stop to the spread of zombie infection.[citation needed]