After divorcing her husband, Natsumi began living with her only daughter, Kyoko, in an old house. However, a few days after moving in, the bath broke. It was summer, and feeling uncomfortable with their sticky bodies, Natsumi and Kyoko headed to the "Senjoyu, a women's only public bathhouse" given to them by the newspaper delivery man... However, at Senjoyu, Natsumi was somehow taken to "Shirayuri," a different bathhouse from Kyoko's. There, Natsumi met Natsuko. At that time, Natsumi had no idea that "Shirayuri" was a "bathhouse for lesbians only."