It looks like there have been some mysterious vampire-like murders going on, and who else does hyperactive, loud-mouthed Rion suspect but Suou, a devishly handsome worker of a male host club. (Well, along with everyone else working at the club) This story is cuter and more lighthearted than Kaori Yuki's typical works, but it's still got all those Kaori Yuki elements in there.