Mito Yamamoto's stunning looks attract hordes of women to the restaurant where he works, causing the owner to finally let him go. Unemployed and without a home, Mito stumbles upon a café and gets cut by a shard of glass. A bizarre man named Ruka Saotome offers to help but instead licks Mito's blood and dismisses him. Later, Mito falls off a roof and is caught by Ruka, who reveals himself to be a vampire.
Ruka confesses that male blood tastes revolting, and unloved blood is even worse. Since he cannot drink from females, Ruka has been seeking a ravishing boy to be his servant. He proposes that Mito fits the bill and invites her to stay at the Hijirigaoka Boys' Academy hostel to develop a connection. The hitch in the plan is that Mito is really a girl!