It's been a long winter for mankind, which was deposed from its throne after losing the epic fight against vampires. A small city-state surrounded by a gigantic wall of light has become one of the human race's last strongholds, its rulers seeking to reclaim control of the globe they have lost. Within the harsh city gates, however, young Momo fantasizes about living in peace with humanity's greatest nemesis. Fine, the vampire queen who once loved a human, has decided to leave the battleground. The two had a tragic encounter during yet another vicious conflict, since they are seen as betrayers by their own species. They embark on a journey together in quest of "Eden," a mythical utopian garden of peace.