Modern Japan, Crime-Ridden City "Anaki." Mimi Usazaki, a melancholic university student attending psychiatric sessions, finds herself trapped in the monotony of life. One day, she is caught up in a mysterious experiment and ends up with the consciousness of her estranged brother, Hyō Usazaki—a death row inmate—lodged in her mind. Now, Mimi must navigate her new reality while being drawn into a deadly battle against other death row inmates who were part of the same experiment…!