Ryunosuke is having a good day when he meets a man named Mister Brown. Mister Brown was one of the innocent bystanders poisoned by Yamiororo during his battle with the Shinkengers. After seeing the Shinkengers transform and rescue the city, Mister Brown dubs himself their number one fan and begs to be taught the ways of Bushid?. The group decides to have Ryunosuke run Mister Brown through a grueling training regimen, hoping that Mister Brown will quit out of frustration. Ryunosuke feels guilty about the deliberate intent, deciding to encourage him not to give up. Mister Brown, feeling that he is learning well, is so encouraged by his supposed progress that he places himself in harm's way when the other Shinkengers take on the Ayakashi Hachouchin. Hachouchin is on the brink of defeating the Shinkengers when he retreats, needing to rehydrate. Later, when Mister Brown meets up with Ryunosuke for his next training session, Ryunosuke tells him that he cannot train Mister Brown anymore and leaves. Mister Brown misinterprets Ryunosuke's words, thinking that he has mastered his training, and joins the Shinkengers as they prepare to confront Hachouchin the next day. After Hachounin's sucker punch nearly kills Mister Brown, Shinken Blue launches the first assault against Hachouchin, and the other Shinkengers follow suit before Hachouchin takes all five down easily. Mister Brown implores the Shinkengers to keep fighting, which revitalizes their fighting spirit. Shinken Red hands off the Rekka Daizanto Oozutsu Mode to Shinken Blue, who, alongside Mister Brown, uses the Kajiki Five Rings Bullet to destroy Hachouchin's first life with Tenku-Shinkenoh destroying the Ayakashi for good. Afterwards, Mister Brown announces that he is returning to his home country to teach Bushid? to his fellow citizens, and Ryunosuke and the other Shinkengers wish him good luck.