Dude has to impregnate every single chick in his high school to save them. From what you ask? Fuck knows. As a wise man once said - Fap first, ask questions later.
In a particular village, young girls are sacrificed to the ancient tentacle god "Izanami". Two brave souls, Aoi and Kusanoou, are determined to stop this barbaric ritual and hopefully not get prodded in the process.
