The plot centres around Maya, the daughter of the former Headmaster of Waldstein Academy, and Fumiaki Uchida, a time traveling agent. The planet had been conquered by aliens in 2012, and time travelers were sent back to 1999 to discover and destroy the Nostradamus Key, which Nostradamus Prophecy said would bring about the apocalypse. The narrative then shifts to 1999, when Maya returns to the Academy with the purpose of destroying it by taking over her late father's role as principal. Her plan was thwarted when she met Fumiaki and learned of the impending disaster. Despite their mistrust of Fumiaki, they agree to search for the Nostradamus Key.