A powerful foe appears from Bunta's past. While mulling over what to do after high school graduation, Takumi is recruited for Ryosuke's new racing team to compete outside of Gunma. Kai Kogashiwa, a street racer and former go-kart racer from Tochigi, appears in Gunma and challenges Takumi on his home base of Iroha-zaka. What Takumi doesn't know is that Kai's father has a long-running rivalry with Bunta. Will Takumi understand Bunta's cryptic hints on how to defeat Kai?