Mayu and Yuzuka, childhood friends and best friends, walk down a mountain instead of hiking on the way back from a short trip, but get lost on the mountain path. The two haggard girls are rescued by a man named Taichi, a beast who makes it a daily routine to bring women to his mountain lodge, where he and his father live, and rape them. The two are unable to resist, so he pins them down and gang-rapes them without any contraception. Local yakuza members who have their eye on their actions get involved, and the two are reduced to sex slaves, gradually losing their personalities...