After stumbling across a haunted go board, Hikaru Shindo discovers that the spirit of a master player named Fujiwara-no-Sai has taken up residence in his consciousness. Sai awakens in Hikaru an untapped genius for the game, and soon the schoolboy is chasing his own dream--defeating the famed go prodigy Akira Toya!

When Hikaru convinces go master Toya Meijin to play Sai online, the meijin raises the stakes: if he wins, "sai" must reveal his true identity; if he loses, he will quit the game forever! Then, Hikaru challenges himself by playing Kurata 6 dan. How do you win a game in which both players use the same color stones?!