After receiving spare parts for the Build Burning from his sister China, Yuuma is on his way back to the lodging house when he runs into a gang of delinquents. Yuuma risks himself to protect the parts, and is saved when Sekai and the others come running over. Meijin Kawaguchi spots someone hiding behind a tree watching the situation and tells him to come out. The person who appears is Junya Inose, a senior pupil who once studied the Jigen Haoh school of kenpo along with Sekai and Mirai. Sekai cannot hide his shock at this sudden and unexpected reunion, and wonders why the Junya who was once so kind would resort to such dishonorable tricks. Afterwards, Mirai tells him that Junya is listed as an alternate team member from Tenzan Academy, representing Miyagi Prefecture, their opponent in the upcoming quarterfinals. To determine Junya’s true intentions, Sekai must put his own feelings into his fist and challenge him in battle during the quarterfinals.