The year is 20XX.
A strange fossil is discovered in Shizuoka City.
It's a find of the century, and scientists from around the country have come to investigate it.
Protagonist Sayoko Kishimoto is one such researcher from Shizuoka.
Piled on with the stress of sexual harassment from her boss, and unfulfilled sexual desires,
she has buried herself in her study of the fossil.
One day, the city is suddenly assaulted by a mysterious lifeform.
The men are killed, and the women are violated, and forced to birth their offspring.
3 days later, and no help is coming. Supplies are running low.
Sayoko's only choice is to try and escape...