Kouhei Morioka, a freelance photographer from a family of exorcists who seems to have inherited none of their power, travels to a German castle on assignment and meets Hazuki, a young vampire held captive there. Hazuki bites him and declares him her servant, only for the bond to have no effect at all. She follows him back to Tokyo and moves into his grandfather's antique shop, where Kouhei, his exorcist cousin Seiji and the rest of the household are pulled into cases of talking cats, spirits and other supernatural intrusions, while Hazuki keeps searching for the mother who left her.