Shinmu Minowa, an ordinary office worker, is visited by his elementary school classmate, Kurofuji Mayu. Known as the Black Witch, she reveals a shocking truth to him. All their former classmates are dead. And soon, they too will die—.Transported to the past by Maiya's magic, leaving only his soul behind, Shinmu begins acting alongside classmates who also time-traveled, determined to escape their fate of death! A powerful duo's time-slip mystery begins!!