Fumiaki Uchida, a time agent, was sent to the past to find and destroy the Nostradamus key that will ultimately be used to create an apocalypse and destroy the earth. On the Other hand, on 1999, Maya Kumashiro, an heir on the Waldstein Academy and has hate occult because personal reasons, attended his father's funeral with an aim to destroy all occult related stuff including the school.
But after accidentally meeting Fumiaki Uchida on the school rooftop one afternoon, her plan was suddenly change to helping him, having knowing that an apocalypse will happen and that in the near future aliens will destroy the world. The only thing that can stop the event to happen, is to find the key and destroy it before July 21, for them to change the future and save humanity. Thus,The start of their search and encounters of different supernatural beings.
