After fainting at work, a young woman wakes up in the back room of the café where she is employed, having lost all memory of her life and the people around her. Two friends, whom she soon discovers are named Shin and Toma, are called upon to help her get home safely. Once she is alone, she encounters a spectral boy named Orion, who is visible and audible only to her. He explains that her memory loss resulted from his chance visit to her world, and he vows to help her remember who she is. However, recovering her lost memories without worrying those around her may prove more difficult than she realizes. In addition to the gloomy Shin and the protective Toma, she must be wary of arousing the suspicions of the captivating Ikki, the quick-witted Kent, and a mysterious man who lurks in the distance. As her amnesia entangles her in the lives of each of these men, her fragmented memories return piece by piece, and the mysteries of her circumstances slowly come to light.