Police Detective Hoshino (Kanji Tsuda) investigates the murder of a maid at a mansion belonging to Miyako Rozmberk (Sugimoto), a seductive vampire mistress and "cougar" all in one. Ukyo Kuronuma (Jun Kaname), an Edo-era swordsman who was turned into a vampire by Miyako is fingered for the crime but before anything can be done about it Hoshino ends up under Miyako's spell as well. This leads Hoshino and Ukyo to battle one another for the privilege of staying with Miyako for eternity.