Sixth grader Hikaru Shindo stumbles upon a mysterious Go board with a blood stain on it. Before he knows it he's hearing voices, one voice to be exact. The voice of an ancient Go instructor, Sai of the Fujiwara. Sai occupies a space in Hikaru's mind. Hikaru is the only one who can see, hear, or talk to Sai. Sai's one and only desire is to play Go. But he can only do that via Hikaru's body. However, Hikaru has no interest in playing Go. Will Hikaru allow Sai to play? And who is this mysterious young boy, Akira Touya?