In a world where witches wield extraordinary abilities such as ESP and telekinesis, Robin, a 15-year-old practitioner of the craft, travels from Italy to Japan. Here, she joins STN Japan Division (STN-J) as a new recruit, filling the void left by a deceased witch hunter. Setting STN-J apart from its counterparts, this organization seeks to apprehend witches alive, delving into the mysteries behind their origins and powers.