Male student Souta Tsukishima begins working at his family's public bathhouse as a back washer. While concealing her true identity, Souta's classmate Aoi Yuzuki visits the bathhouse. A relationship between the two begins to develop when Souta washes Aoi's back.
When 15-year-old Rihito falls in love, an ancient vampire who craves 18-year-old virgin blood must protect the teen's virginity at all costs.
After Mizusawa Yume's mother becomes ill and passes away, she finds a picture of a man holding a baby in her mother's keepsake box. On the back of the picture it says "Loving Papa and Yume, at Raku no Yu." Yume has never known or even seen a picture of her father, but she believes that this guy must be him. Also in the box there is a lighter with the initials RM.
After she finds that the "Raku no Yu", is a 'sento' (public bath) in Shibuya, Tokyo, she's off to meet her long lost father and to get as much money out of him as possible. The debts her mother left her after her death left nothing for Yume. Yume blames her father for her mother's death because if it wasn't for him she wouldn't have had to work so hard and wouldn't have gotten ill and died young.
Once she arrives in Tokyo and finds 'Raku no Yu' she finds a name plaque with the inscription Mannaka Rokku, so she is sure this is the place.