Everyone is anxious to find out just who this mysterious user named "Sai" is. How long can Hikaru keep playing before he gets caught?

Hikaru is slowly, but surely, getting better as evidenced when he beats Mitani in a game though with a handicap as well as Tsutsui. To play go with Sai, now that they decided not to play internet go anymore, Hikaru tries to get his gramps to buy him a go board/stones. When Hikaru beats a strong opponent at the go school, even to the astoundment of the teacher, he finally understands that one can only judge how strong others are when he's strong himself. He bumps into Kaio's first board when he's browsing a bookstore and the latter pulls him away to a match.

The top 16 in the A league all take part in the Young Lions Tournament. If Hikaru can manage to get past the first round, he'll finally get to face Akira again. Meanwhile, Isumi faces an old rival, and everyone wants Isumi to put him in his place. As Sai and Ogata monitor Hikaru's game, they become shocked when Hikaru turns a bad move into a good move. However, when the round ends, only 3 Insei will have made it to the next round.

Hikaru discovers that Sai is missing and searches all over him. Unable to locate him, he travels to Inno Island to visit Shusaku's grave in an effort to find him. Is it true? Is Sai really gone?