An isolated island, inhabited by warring vampires and humans, and surrounded by aquatic demons that foil any attempts at entry or escape that are not explicitly authorised by their vampiric overlord , Miyabi.  

Ryousuke, his girlfriend Kazumi, and his friend Yamaoka are shipwrecked by the demons, and wash up on the shore of Higanjima. They soon experience the monstrous cruelty of the island's vampires first-hand but, luckily, Ryousuke is able to join up with the human resistance. …however, mainland Japan may not be safe for long either. If the vampiric threat is not eradicated in 47 days, then Miyabi's machinations will transform it into yet another vampire island!