Hikaru Shindo is a young boy who discovers an old Go board that has a mysterious bloodstain that only he can see. sealed into the Go board is a spirit named Sai. Sai was a Go instructor from long ago, but drowned himself in a lake after being exiled from the Capital. He then becomes attatched to Hikaru and teaches him about GO. Hikaru begins to take an interest in this game and pursues a life of Go. Go is fun and enjoyable by people of all ages.