In the mid 21st century, the human race is facing a test.
Genetic engineering has changed the world, and with huge profits,
research had accelerated accordingly. An “immortality” gene no longer seemed like
a mere dream. However, a lab sample containing this gene escaped, creating a new life-form that took in genetic material from the natural world, evolving into an enemy that began to invade the human world.
The “Shaher” are now a force capable of defeating human military forces,
and both North and South American continents have fallen under their control.
In Japan, the government has created a “Samurai” unit to oppose the Shaher,
utilizing soldiers enhanced with nano-machines to connect with an armored exoskeleton.
It is at this point that Tsukahara Takemichi is assigned to the first platoon of the “Samurai Force”.