When the skeptical Ryouta Murakami and the ambitious Kuroneko ventured into the woods to establish the existence of alien life, a horrible event occurred, taking Kuroneko's life and leaving Ryouta seriously injured. Ten years have passed since the catastrophe, and Ryouta is now a typical high school student. In memory of his late companion, he pledges to prove that aliens exist. Neko Kuroha, a transfer student, arrives suddenly one day, striking a remarkable resemblance to the late Kuroneko—even having a similar name. Most bizarrely, she appears to have otherworldly abilities. As Ryouta becomes increasingly interested in Neko, he is lured into a dark world where sinister scientists seek magical-wielding witches who have gone missing.