The era is Taisho. Himena, who gave up her dream of becoming a teacher and was about to be forced into a marriage ceremony with her violent fiancé, was saved by Shiratori, a vampire who has lived for hundreds of years by absorbing human blood. Himena is contractually married to a kind vampire who has suffered a deep emotional trauma. Himena can only offer blood to Shiratori. Her heart must not be taken from her... even though she knows she must not love him....