The narrative takes place in a tranquil, futuristic society established by the Manifestation Engine, a device that resolved an energy crisis five years earlier. On Izu Oshima island, Akane Isshiki enjoys a quiet existence with her relatives. As an extraterrestrial threat called the Alone endangers the globe, her grandfather, Kenjirou, hands her a unique key. This item enables her to enter the Vivid System, bestowing upon her extraordinary abilities. Accompanied by her companions Aoi, Wakaba, and Himawari, Akane battles to safeguard the world against the Alone.