A Mahjong gambler is in a tense game for his life, as losing means death in order to acquire the debt owed from his gambling with life insurance. Akaki, a middle schooler, enters the mahjong parlor, changing the atmosphere of the game.
Akagi displays a deep understanding of mahjong, so much so that the Yakuza call Yagi, a high-level player to step in. Akagi shows his aptitude for, not only mahjong but also high-stakes situations as Yagi gives him a personal wager.
It's a game of psychological warfare between Akagi and Yagi as the two both attempt to bluff the other into submission while also adding sleight-of-hand tactics too. Akagi is however unfazed and continuously playing aggressively.
Having seemingly gotten Nangou out of a bind, Akagi decides he wants to use Nangou's money he won to enter another high-stakes mahjong game worth 8 million yen, with 6 million coming from Nangou and the other 2 from Yasuoka.
As Akagi was late to arrive at the match's location and because it was impossible to postpone the match, Nango plays on Akagi's place. A rule that states the match will continue until Ichikawa or Akagi expend all of their points is set.
Ichikawa now goes on the offensive by targeting Akagi directly, proposing a Zetsu Nimon-the two discard pin and tiles. Akagi loses the round but avoids losing the match.
After a break, Ichikawa tries to switch Akagi's drawn tile but Akagi stops him. However, Ichikawa changes the dora indicator tile, which in fact Akagi induced him to.
Six years after the match between Akagi and Ichikawa, Yasuoka presents a man claiming to be Akagi to Kawada, the boss of a yakuza group, of whom requests proof of this Akagi's skill as verification.
Akagi gives the correct answer but the fake Akagi says it was only logic, as these were the remaining tiles, and that three was statistically the best answer. Akagi says he is wrong, then the man challenges him.
After Akagi beats them all, Ishikawa arrives and takes him to see a match between fake Akagi and Urabe, a representative player of Fujisawa yakuza group. Fake Akagi is winning but Akagi says that Urabe is losing on purpose.
Akagi rejects several opportunities to win, and Urabe wins the hand, widening the difference. After several coincidences, Akagi wins the next hand and cuts the difference. In the final hand, Akagi induces Urabe to deal the tiles he wants.
Urabe discards a 2-pin, which Ishikawa reveals to be the tile Akagi wanted to win. Kawada asks to Akagi to explain how he had sure Urabe would discard it. He used Osamu to learn about Urabe's habits and style of play.
When several man are deceased with blood loss extracted from their arm by a serial killer, Yasuoka identifies one of them, Hirayama Yukio, the fake Akagi.
Akagi agrees to follow Yasuoka to track down the murderer to play mahjong with him. The murderer is revealed to be a police officer who accumulated wealth through consulting and blackmail who has begun killing people in games of mahjong.
Unfazed, Akagi asks to raise the stakes so that he would be able to witness Washizu's destruction. Enraged at Akagi's arrogance, Washizu demands that Ogi explain to Akagi that this is not a mere game.
Akagi earns 1 million yen from Washizui from the previous round. Yasuoka plays a discard into Akagi's hand allowing Akagi to win the next round. Yasuoka's own points do not matter as this is primarily a match between Washizu and Akagi.
The match enters the south round. Washizu is in a favorable position, with a single wait for a sanshoku hand and 1 dora. He is convinced in his victory, but ends up dealing into Akagi's hand as soon as he declares richi.
The first round ends with Akagi in first place. However, Akagi refuses to regain the 1100cc of blood that he lost, instead demanding all his winnings to be redeemed into money.
Having read through Washizu's hand, Akagi headbumps the 3-Man tile that Suzuki deals to Washizu. This causes the winnings of the first and second round to reach ¥118,500,000
Washizu's hand takes the form of 6 dora tiles. If he gets a self-drawn dealer baiman win, Akagi will die. Washizu finally gets to see Akagi's face trembling in despair.
Washizu's hand takes the form of 12 dora tiles. If he gets a self-drawn dealer counted yakuman win, Akagi will have 1600cc of blood drained from him, far exceeding the lethal dose.
Having escaped from the dire situation, Akagi instantly takes on an offensive stance against Washizu. Washizu completely loses his composure from Akagi's words.
