Sōsuke Banki!? is the twelfth episode of Engine Sentai Go-Onger.
While the other Go-ongers are practice sparring with each other, Sōsuke is laid up with a cold and has been resting inside the Ginjiro-go for the last three days. The Ministers send Hatsuden Banki into the city to discharge lightning and cause mayhem. Despite his cold, Sōsuke rushes to confront Hatsuden Banki, who is none too impressed by Sōsuke's confidence. When Sōsuke executes a close range attack, Hatsuden Banki's generator overloads and discharges a bolt of lightning that zaps them both and switches their bodies. The other Go-ongers find who they think is Sōsuke (but is actually the soul of Hatsuden Banki in Sōsuke's body) and bring him back to the Ginjiro-go, while Sōsuke, whose soul is trapped in Hatsuden Banki's body, awakens in confusion in front of Yogostein. Each sees a golden chance to destroy his enemy from within, but Hatsuden Banki is waylaid by the other Go-ongers' earnest, yet bizarre, attempts to cure "Sōsuke" of his cold, and "Hatsuden Banki" is set to have his power amplified for Yogostein's "Plan B." When "Hatsuden Banki" destroys the generator that has amplified his powers, "Sōsuke," who has escaped from the Go-ongers, shows up and tries to convince Yogostein that he is really Hatsuden Banki. "Sōsuke" and "Hatsuden Banki" start battling each other, and just as Yogostein figures out the situation, the other four Go-ongers arrive. Yogostein grabs "Sōsuke" and threatens to kill him if the Go-ongers do not defeat "Hatsuden Banki." However, the Go-ongers see right through Yogostein's plan, thanks to Speedor, and attack "Sōsuke" instead, forcing Yogostein to retreat. "Sōsuke" turns into "Go-on Red" and fights the Go-ongers, but is knocked down by "Hatsuden Banki." Speedor and his fellow Engines combine their powers to draw Sōsuke's soul from "Hatsuden Banki" into a Soul Chip, which the Go-ongers place in the Junction Rifle and fire at "Sōsuke." Both souls are returned to their rightful bodies, but Sōsuke's cold remains in the body of Hatsuden Banki, which weakens the beast enough to be beaten by a Speedor-powered Super Highway Buster. Hatsuden Banki then Industrial Revolutionizes, but he is still hampered by Sōsuke's cold, which allows Engine-Oh G6 to scrap him easily. Later on, back on board Ginjiro-go, Sōsuke asks why the other Go-ongers did not realize the body switch sooner than they did. Gunpei's explanation soon devolves into an argument between him, Renn, Saki, and Hant about the cold cures each was administering to "Sōsuke," and they ignore Sōsuke's pleas to get them to stand down.