Marina and Airi's single mother has recently gotten married. Their new step-dad seems like he'll make a loving father. Like a really, really loving father.
Takato Keisuke and six females are locked up in a dungeon underground. According to the rules, the only way to escape from this place is to rape all six of them. One by one. Can they escape from here and go back to being normal? Or is this going to change them for the worse?