Following their narrow victory against Purple Shadow, Project D's reputation is at stake after a pair of imposters parade around Saitama. Initially Takumi seems oblivious to the incident, but takes notice after he is mistakenly blamed for taking advantage of a girl. Meanwhile, the final stage of Project D's expeditions is upon them, and is to be the hardest yet.

The first stage of Project D's Kanagawa expeditions is against Team 246: Satoshi Omiya and Kobayakawa. Although racing for their own pride, 246 are actually part of a grand plan initiated by Team Sidewinder's Go Hojo and Eiji Kubo. As the uphill race begins, Kobayakawa is about to be shown the true ability of Keisuke Takahashi.

As the first battle winds down, the downhill between Takumi’s Eight-Six and Omiya’s NB8C Roadster begins. As both cars reach their limits, the control of the drivers will determine the outcome. Against Omiya’s miraculous car control, will Takumi be able to win? Another factor will come into play.

Kanagawa's Second Line will be against RT Katagiri, where Takumi encounters Kai Kogashiwa: a former rival from Irohazaka; graduated from street racing and now a professional racer with his MR-S. However, Takumi is starting to show a "Zone" that had evolved from the Purple Shadow races, a zone that even Ryosuke cannot explain. The winner of this race is up in the air.

As the battle heats up, both Takumi and Kai both use all of their ability, and then some, to battle for the win. In the next battle, Keisuke puts his new accelerator techniques to the test against Minagawa's Supra. But as Ryosuke explains, there is another purpose of this training that would allow him to beat the "super-orthodox" pro racer.

As it appears that the FD vs. Supra battle is giving no quarter, the question is, is it possible for Keisuke to hold off Minagawa's professional pressure? Meanwhile a new racer appears on the slopes of Hakone, and its evident he wants to kill himself, and take anybody with him!

Keisuke's next opponent in Kanagawa's Four Lines of Defense is the leader of Team Spiral, Ryuji "Zero" Ikeda. Ikeda believes in his "Zero Theory", where the driver thinks of nothing except being one with the car to create the ultimate racer. Quite similar to Ryosuke's Fastest Racer Theory, Ryosuke also notices a few flaws in Ikeda's theory. A flaw that would arise as the wet conditions create a fog battle.

The downhill battle between Takumi and Hiroya "Zero 1" Okuyama's S15 starts, with Okuyama waiting to attack until the later section because of the fog. However, he hasn't considered the ability of Takumi's adaptibility skills. Whilst this is on, another battle is in the midst: Ryosuke's inevitable battle with the driver known as 'Shinigami', Rin Hojo.

The destined battle between Ryosuke and Rin 'Shinigami' Hojo has begun, over a girl named Kaori. As the race progresses on, the story of Ryosuke, Hojo and Kaori is revealed. And as Ikeda of Spiral Zero spectates the race from behind, it's obvious that this race of fate has quickly risen well beyond dangerous.

As the battle get more dangerous, several confessions come into play that create the full picture behind the feud between Ryosuke and Rin, and how Rin's actions played a huge part in Kaori's suicide. But as they approach the end of the track, Rin's tires and brakes are completely shot, turning his R32 into an unstoppable weapon.

As the out-of-control FC and R32 hurtles down the mountain, only a miracle can stop these two missiles from spectacularly crashing! Meanwhile, Project D prepares for their last battle of Kanagawa against the secretive Team Sidewinder. That is, until the SpeedStars find out that Takumi’s opponent will be an Eight-Six.

The final battles for Project D are here, and it all starts with the uphill battle between Keisuke's FD and Go Hojo's NSX. But as Rin understands, there is a fundamental difference between his younger brother and Keisuke, one that might determine this race.

The battle between Keisuke and Go Hojo continues. Keisuke's good run behind Go Hojo led to many feeling unbelievable, including Go Hojo himself. Then entering the second round, the match gets more intense. Who will take this uphill climb battle?

The intense hill climb battle between Keisuke and Go Hojo is coming to the end of second round. Keisuke engages in attack mode and Go Hojo starts to get tense. Meanwhile, Shinji Inui has revealed to especially Mako and Sayuki, who has been with him, that he would be the racer of the downhill battle against Takumi.

Takumi and Shinji's match thus kicks off on an instant. Shinji is given the lead. Bunta steps out of the tofu shop and breaks his key pouch after accidentally dropping it. Bunta speculates an unfortunate event that will happen. Shinji starts to show his dormant power, leaving Takumi to be shocked himself.

Takumi and Shinji continue with their match with Takumi, still bewildered by Shinji, starts to focus. But suddenly, Shinji allows Takumi to pass, which disturbs Takumi even more. Even Kubo is utterly disheartened by the turn of events, but both Go and Ryosuke believe this was inevitable, creating a suitable conclusion to Project D's expeditions.

Both drivers are equally strong, towards the middle of the race. They face a battle of gaining the lead.

The intense downhill battle between the two drivers are reaching an end, as Takumi and Shinji race to their absolute limits. As this battle comes to a close, and the reign of Project D finally ends, the true meaning behind the "D" will be revealed. As the characters go on different paths, Takumi's passion to be "the fastest one out there" will never end.