Emperor, a team of Lan-Evos from the Tochigi prefecture has arrived with the goal to crush every team in Gunma. Soon they realize the fastest car in Gunma isn’t just Akagi’s White Comet, but also a new downhill legend known as Akina’s Eight-Six.

What would happen if the Eight-Six gets a new upgrade? That’s exactly what Iketani and Itsuki has been thinking about to increase the performance of Takumi’s vehicle. But would Bunta allow it? Elsewhere, team Emperor’s winning streak isn’t slowing down as they continue to sweep across Gunma, defeating every race team with ease. Their next target: Akina’s Eight-Six.

Kyoichi senses an uncanny fighting spirit within the Eight-Six’s driver, as he gives Seiji strict rules against the race. Seiji however decides to ignore these rules and launches his Evo IV into full power. Takumi is outclassed in almost every category as the Evo IV’s power is truly amazing. The battle risk escalates when the race reaches the second half of the course.

In his heart, Takumi cannot accept his victory over the Evo IV and decides to make a vow. To add to his already uneasy thoughts, anonymous messages are being sent to Takumi concerning his relationship with Natsuki.

Takumi soon discovers Natsuki’s secret that leads him to vent his anger in an egotistic battle against Kyoichi at Akagi, thinking little of the huge disadvantage he has.

Kyoichi is realizing just how incredible Akina’s downhill specialist is, yet he has full confidence in his rally tuned Evo III. Takumi soon realizes the difference between the Eight-Six and the loud banging horsepower of the Evo III.

With the Eight-Six out of the picture, the RedSuns has become the main representatives of Gunma, as every local racer within the prefecture are in favor of Emperor’s defeat. Ryosuke has returned on the street to defeat the revenge-seeking Kyoichi, who plans to use his theories of Motorsports against the White Comet. Also, Iketani and Kenji spot another racer from a neighboring prefecture.

Mount Akagi’s battle continues as Ryosuke has his own theories about streetracing, and he plans to demonstrate its difference on Kyoichi’s Evo III. Back in Akina, Takumi’s routine way of life is gone with the absence of the Eight-Six and the discovery of Natsuki’s secret.

The Eight-Six has returned undergoing a major change. Takumi soon test-drives the new performance much to his mixed satisfactions and disappointments, but what he doesn't understand is what Bunta knows what’s within that car. Also, the relationship between Takumi and Natsuki is falling apart, but Itsuki’s heart is shaken with the appearance of Kazumi.

After Wataru issues a short-lived battle against Keisuke, his sister Kazumi introduces him to Itsuki leading to a chance meeting with another Eight-Six driver. At first everything seems right with the meeting, but because of Takumi’s naïve reaction to his car’s new downhill weapon, Wataru rubs it the wrong way as his bad side emerges.

Takumi takes up the challenge and decides where the battle would take place. But before he can accept Wataru’s challenge, he’ll have to learn the most basic essentials of what it means to be a street racer. Also, Itsuki’s relationship with Kazumi is teaching him the value of having a girlfriend.

Takumi is about to experience a completely different type of racer within Wataru’s own Eight-Six, in a treacherous mountain pass consisting of mixed elevations, rusting guardrails, unexpected traps and aging rough pavements. As Takumi presses down the accelerator, the true nature of the Eight-Six’s new hidden weapon emerges in its monstrous raw performance.

The battle between the two Eight-Sixes have met Wataru’s satisfaction much higher than he expected, but he plans to decide the outcome of this battle with the judgement of the human body’s limitations. Takumi soon realizes he is losing grip of his pace. After the battle, a series of revelations take place among all the characters in preparation to what’s coming next.