Its central characters are a vampire girl named Miyu and her demonic companion Larva. Miyu is the daughter of both a human and a shinma (demon) and as such she was awakened as the guardian whose destiny is to hunt down all stray shinma and send them back to the darkness.

A young biker stumbles onto a prototype motorcycle with a hidden function that has a link to the true nature of his world.

Years after the events of Megazone 23 II, the only city on Earth is the supposedly idyllic Eden. There lives Eiji Takanaka, a B Level hacker who has just been accepted into EX, the organization that controls Eden. However, before his first day on the job, he becomes embroiled in a network war, a legendary figure named EVE, and a plot to re-inhabit the Earth.