As childhood friends and best friends, Kiyori and Mio, who attend the same university, had come to a mountain village in a certain prefecture for a trip. They stayed at a fashionable camping site that was popular, and instead of hiking, they decided to walk down the mountain, but they got lost in the unfamiliar mountain. Wandering around, they found an old inn... There, they encountered men who were like beasts hungry for women. They attacked the two young and healthy girls, and with several companions, they engaged in a thick insemination. Eventually, Kiyori and Mio's personalities collapsed, and they fell into becoming masochistic females.