The story a boy named Ryota Murakami and his female friend he calls Kuroneko. The two had a close relationship as they look up at the stars in the sky. Kuroneko insists aliens are real and attempts to show them to Ryota, but they fallen into an accident. Ryota survived, but, the doctors claim Kuroneko died. Feeling regretful ever since, hoping to atone for Kuroneko, Ryota kept looking at the sky, aiming to become a researcher at NASA as to prove the existence of aliens. Ten years later, Ryota a top student in high school. Then a transfer student named Neko Kuroha enters his classroom, surprisingly, she looks exactly like Kuroneko! However, Neko doesn't recognize Ryota. During swimming lesson, while Ryota does consideration on Neko, a student almost drowned but is saved by a mysterious force. Ryota goes to the observatory as the sole member of the astronomy club. Neko comes in to inform Ryota that his death been predicted, but he doubts it. As the two come know each other, Ryota becomes suspicious of her. Ignoring Neko's warning, Ryota leaves for home without getting on the bus, and then a mudslide suddenly comes down on him. When a boulder is about to crush him, Neko splits it with strange powers, saving Ryota. Showing a harness attached on the nape of her neck, Neko reveals to him that she is a witch.