As the Go-on teams celebrate S?suke's recovery and their victory over Yogostein, Renn is inside the Ginjiro-go, hard at work on a new weapon. While Renn's back is turned, the Ancient Engine Souls jump aboard S?suke's RC truck and flee the Ginjiro-go. Kegalesia speaks at the Gaiarks' wake for Yogostein, only to be interrupted by a commotion caused by Kitaneidas, who had promised to avenge Yogostein, and had created a powerful Savage Machine Beast to do just that. The Go-ongers finally discover that the Ancient Engines are gone, and they split up, frantically searching the city for them. Renn's search leads him to the Sut?s' villa, where he finds the Ancient Engines hiding out. Kishamoth, T-line, and K-line blame themselves for the events that led to S?suke's brush with death and had run away, feeling unworthy of being partners with the Go-ongers. Renn tries to assure the Ancient Engines that no one, especially S?suke, blames them for anything, and presents the weapon he created for them, which he calls the Kankanbar. Meanwhile, the other Go-ongers run afoul of Kitaneidas and Kegalesia riding in Engine Banki, a Barbaric Machine Machine based on Engine-Oh itself. The Ancient Engines are still not convinced that they can help, so Hiroto volunteers to talk to them as Renn and Miu leave with Bus-on and Jetras to aid Gun-Bir-Oh, Bearrv, and Speedor against Engine Banki. Unfortunately, Engine Banki is more than GunBir-Oh, Go-Roader, and Engine-Oh Jetras can handle, and he breaks the combinations. The Go-ongers remain undaunted, using everything at their disposal to battle Engine Banki. As everyone at the Sut? villa watches the Go-ongers fight valiantly, Hiroto pours out his heart, telling the Ancient Engines that, in the same way that they had protected the dinosaurs, he and his friends will risk their lives to protect those they care about. The Ancient Engines finally understand and agree to fight side-by-side with the Go-on teams. Go-on Gold arrives at the battleground and uses the Kankanbar, powered by T-line and K-line, to shrink Engine Banki and force Kitaneidas and Kegalesia to abandon ship. Go-on Gold hands off the Kankanbar to Go-on Red, who links the new weapon with his Mantangun and uses the Kankan Mantangun, powered by all three Ancient Engines, to scrap the Savage Machine Beast. Afterwards, the gang admire the Kankanbar and are happy that the Ancient Engines have returned to the fold, but when Toripter announces that Hiroto's "fiery persuasion" was what brought the Ancient Engines around, the attention shifts; everyone begs to know what exactly the normally stoic and aloof Hiroto had said, as he tries to modestly shrug it off as no big deal.