In 2030, Japan.
A disease has infected humans throughout the world.
Infected people turn into different forms of monsters based on their ages, sexes and races.
The disease is named ‘Gibia’ - after being rich in variety like gibia.

Just then, a pair of samurai and ninja appeared in such a blighted wasteland of Japan.

They both travelled from the early Edo period, fighting together with help from a doctor who tries to find cure for Gibia.

Facing ceaseless attacks from Gibias, and outlaws that attack travelers for food,
they start the dangerous journey with enemies all around.