Mori Ranmaru, a 450-year-old vampire, has spent a decade working at the Koi Bathhouse and watching over Tatsuno Rihito, the family’s 15-year-old heir. As Rihito starts high school and falls for a girl he meets on the way, Mori sets out to protect the boy’s virginity until he turns 18, while the Tatsuno family gets involved in his new romance.
