In the Midori Mahjong parlor, Nangou is trying to cancel his major debts by playing some Mahjong but this may be his unlucky day as he is losing badly. Just when the situation gets dire an unknown boy walks in on their game and with a simple word of advice and Nangou is able to survive. This may be the beginning of the legendary Shigeru Akagi who will shake the underworld.

On a stormy night, after winning his first hand of Mahjong, Akagi continues playing against Ryuzaki and his gang members, as he slowly awakens to his latent talents. Akagi quickly turns the tide in his favor and takes the lead, so Ryuzaki calls in his last resort, Rep player Yagi.

The silent battle between Akagi and Yagi ensues and nothing else matters except whose judgement in their own actions wavers first. Yagi knows that he cannot beat Akagi fair so he uses a form of cheating called the "caterpillar" in order to utilize the genius Akagi's weakness. As soon as Akagi learns this fatal mistake he decides to counter by taking them for all they've got.