A long time ago, an unknown meteorite came to earth. The meteorite was sleeping quietly deep in the earth, waiting for the time to wake up.
10,000 years have passed, and when humans have built civilization, a change occurs in the meteorite.
Countless alien "breeds" are born from the meteorite and quickly devour the planet.
The true identity of the meteorite was the egg of an alien life form.
The land above is destroyed, and national functions disappear. Humanity is defeated.
Those left behind are forced to live in sturdy underground shelters.
The shelter was named "Ark" and became humanity's last stronghold.
In order to take back the land, humanity has gathered its wisdom and materials and developed two "anti-bleed" combat weapons.
One is the manned weapon “Father”
One is a combat clone soldier with the appearance of a girl who becomes Father's pilot.
They live in a deserted front-line base and then go off to fight.
