The owner of the public bathhouse "Oibore," Matsutakebai, is a thoroughgoing pervert. He always enjoys spying on the women's bath with his perverted friend Zajuro. Kaori Yuasa (played by Honda Riko), a young wife living nearby this suspicious bathhouse, has a clear face but a tantalizing physique that Matsutakebai wants to possess. One day, Zajuro brings a bath additive labeled "Manjun-yu." It seems it can turn any woman into a lascivious female... Promptly, Matsutakebai sabotages the bath at Kaori's home, leading her to come to the bathhouse...