Ran and her family, mother and father and older brother Rin (凜), live in a small but growing town. Ran already has a boyfriend, the quiet Rui (留衣), whom she has known since they were small children. She is looking forward to everything in her new school life. Then on the way to school, she hears a mocking voice inside her head.
As the day progresses, she hears the voice again, now talking to her clearly, and she identifies the 'speaker' as the new student Midori (翠), who seems set to become Ran's personal enemy. After an initial confrontation however, she finds that Midori has been seeking her, having come to her town after sensing another person with strong telepathic powers in it. Midori's parents have effectively rejected her, unable to accept her powers. Ran, more at ease in her home life and confident that her family would still accept her, makes friends with Midori. There is however a real enemy at work in the town. A variety of apparently isolated incidents all have in common that people (and animals) suddenly act out of character. It seems there is someone else with psychic powers behind it all.Haha.
Just next to her she heard a laughing voice, a tiny laughing voice.
Ran turned around.
The room was filled with the the light flowing in from the window. The cats Kishou and Tenketsu were sleeping in the bright spring sunlight. There was nobody there.
The mystery is one of those affairs where there's really only one suspect, though just what the culprit is after leaves some room for deduction or speculation. In general as far as plot is concerned, the book runs a very conventional path, with a thin emotional story progressing in tandem with a thin mystery. Probably the book is best seen as establishing the characters, in particular Ran, Midori and Rui, for later appearances. In the final confrontation, it is Midori, rather than Ran, who is the detective. Ran's role, from this book at least, looks to be more one of emotional guidance.
What I said about the vivid but simple style of Battery applies here too. The story here feels more conventional than that book. It looks like it is meant to be something lighter, mostly humorous outside of a few confrontation scenes. It is also more eventful and progresses a lot more purposefully.