Karin Hanazono is a normal, depressed girl who is feeling lonely after losing her parents some time ago and after her cat "Shii-chan" had recently died. When at the cat's grave one night, a young boy named Kazune Kujyou approaches her, but she gets angry at him when he calls her a moron, punching him in the face for it. A few days later, Karin meets his cousin, a young girl named Himeka Kujyou and then the ring that her mother gave her begins to glow mysteriously...