Hikari has only one friend: Nai-nai, a shadowlike being without a body or voice who lives in her closet. One day, Hikari introduces Nai-nai to a bully from her school named Arisa, and then everything changes. Arisa starts treating Hikari like her best friend, classmates warm up to her one after another, and even her strict mother suddenly begins spoiling her. Realizing something is wrong, Hikari tries to distance herself from Arisa, but that only makes things worse. Meanwhile, a medium named Shiro receives a request to look into the death of a woman who took the lives of herself and her toddler. While these two incidents seem unrelated at first, both are connected to the same powerful curse...