Akira is a special kid. Instead of going out to play like any other kids, he prefers to read difficult books for grown up. However, his parent is deeply concern about him. It's true that he can solves college level difficult questions, but no matter what...he won't talk.
What Akira's parent doesn't know is that Akira is being stalked by a mysterious man that only Akira can see him. That man dress in unusual dress and shows up everywhere even in Akira's room, especially when the subject of god comes to his mind. Akira is severely scared of this man and thinks that if he opens his mouth talking, that mysterious figure will get inside his mouth and take over his body.
Akira remains silence for years until an incident that triggers him to screams out for help loudly. Since then, that mysterious man never shows up again and so does his ability to solves difficult puzzle has gone. Since then, Akira lives his life like nothing happens until one day he's asked about his belief in god. While he gives out his answer, to his horror, he spot that mysterious man again.
Note: The 2nd edition of this manga is included in the silk road series in 1993/94. It have a bit different ending from the original one.