Half a year ago, 3G celebrated the successful activation of AI units GBR-2 (HyoRyu) and GBR-3 (EnRyu). They are subsequently given lessons about science, language, and combat then installed in transformable rescue vehicles. However, they currently lack the energy to transform. Pasdar reflects about his Machine Kings’ repeated failures, and Primada volunteers to command the next attack. Elsewhere, Mamoru’s class is riding the school bus on a field trip, and the conversation turns from Mamoru’s pager to Sunou Takayasu’s collection of gadgets. Back at 3G, Leo wonders why HyoRyu and EnRyu can’t store enough energy in their GS-Ride engines to perform system change and Kazuo suggests it might because their copy of the technology is flawed. A truck driver gets stuck in a traffic jam and tries in vain to found another route. In anger, he punches his navigation system screen, and it shows a route that leads to a dead end. Primada appears in a shroud of smoke and dances around the driver before attaching a Zonder metal crystal to his forehead. The driver yells that he hates traffic and merges with his truck to form EI-06, a giant steamroller. Mamoru senses the Zonder while playing a portable videogame with his friends but he ignores it. Mikoto and Swan discuss the traffic jam, and Swan notes how different lifestyles in Japan and America are. They’re alerted to a large accident on the highway, but brush it off since Mamoru hasn’t contacted them. EI-06 starts tearing up the streets and absorbing the cars it flattens, and the school bus is stuck in traffic. Hana starts noticing Mamoru’s hair changing, but everyone’s attention is turned to the teacher who screams and points at EI-06 heading towards them.
3G finally notices EI-06, and Taiga notes that they took too long to discover it. Mikoto tries to contact Mamoru but Hyuuma says he can’t help them now. Mamoru’s class runs out of the bus, and the former is so racked with guilt for not noticing that he forgets his pager in the bus. Hana tries to retrieve it, but when EI-06 gets too heavy for the elevated highway they’re on it collapses and sends the bus teetering on the edge. Guy rushes to the scene and asks 3G to send the Dividing Driver, but Kazuo tells him it won’t be ready for another two hours. Mikoto suggests sending out HyoRyu and EnRyu, and Taiga asks the brothers if they’re ready. They’re raring to go, and Taiga orders them to launch and assist with the rescue operations. EI-06 continues towards Mamoru and his friends, and GaiGar appears and tries to stop its advance. EI-06 spawns a loader arm and tries to crush GaiGar. From a nearby rooftop, Primada notes that GaoGaiGar can’t be formed if GaiGar is destroyed. The bus with Hana in it falls off the edge, but HyoRyu arrives just in time to grab it with his crane arm. Hana gives Mamoru his pager back, and he apologizes for putting her in danger. Hyuuma arrives with EnRyu and starts evacuating the civilians from the battle. Guy’s just about at his limit when HyoRyu and EnRyu rush to assist him. EI-06 holds them back with a barrier, and Leo says that only system change can save them now. They still don’t have enough energy, and Mamoru curses the Zonder as he glows green again. Suddenly the GS-Ride energy in the 3G robots maxes out to everyone’s shock, and HyoRyu and EnRyu are finally able to transform to their robot modes. HyoRyu uses his Freezing Gun to stop EI-06 in its tracks while EnRyu fires his Melting Gun at its upper body. They distract it long enough for Guy to perform Final Fusion. Guy quickly uses Hell and Heaven to break through the barrier and rip out EI-06’s core while HyoRyu and EnRyu push the main body into the ocean where it explodes harmlessly. From atop Tokyo Tower, Primada seethes with rage and promises revenge. Mamoru purifies the core and apologizes to Guy for not contacting him sooner. Guy tells him that it’s their teamwork that saved the day and HyoRyu and EnRyu introduce themselves. Leo wonders if Mamoru was responsible for the increased GS-Ride output. Later, the truck driver gets stuck in another traffic jam, but this time he simply turns on his music player and says there’s no hurry.
GaoGaiGar is now joined by two new partners. Although they’re keeping with the defensive theme by transforming into rescue vehicles, HyoRyu and EnRyu mix things up by packing guns. They may sound a bit timid now, but their personalities and voices will soon blossom into what the fans know and love. Hyuuma breaks yet another walkie talkie, and Entouji shows us the copious amount of dandruff occupying his hair. Despite being repeatedly thwarted, the Machine Kings are quick to take note of and exploit any weakness in GaoGaiGar they can find, which will make for more dangerous scenarios that Guy will have to overcome in the future.