After Guy’s shuttle accident, Galeon was secretly repaired inside the Space Development Corporation, where a panel of unknown function was discovered on his head. When the recently recovered cyborg Guy touches it, it reacts to his G-Stone and displays a bunch of holographic blueprints which were then used to develop the GS-Ride and subsequently all the 3G robots. The Amami’s and Hana are enjoying their time at Waterpolis, an aquatic amusement park, while they wait for their turn on the new Shooter Coaster ride. Polonaise watches Mamoru from afar and notes that he’ll use him to lure Galeon out. Elsewhere, Taiga, Hyuuma, Leo and Guy are called to a congress hearing to explain the destruction of Isolde. Leo notes to the bored Hyuuma and Guy that if they don’t give out all the details their funding will get cut off. Hyuuma changes the topic and wonders if the Zonder might attack Mamoru directly while he’s on vacation, but Guy tells him not to worry because Volfogg is keeping close watch on Mamoru and his family. Ai and Isamu decide to go into a mirror house while Mamoru and Hana go on the Shooting Coaster. They pass by the park mascot selling balloons and Mamoru is unimpressed by his costume. The man goes to an empty lot behind a building and takes of his helmet, complaining about the job and heat and wishing he could ride on the coaster. Polonaise appears before him and offers a Zonder crystal to help fulfill his wish. The Shooting Coaster starts with Mamoru and Hana on it. It flies off the track and into an underwater tunnel. Suddenly the mascot appears at the front and merges with the ride. He twists the tunnels and makes the ride go faster, causing everyone except Mamoru to pass out. The latter tries to activate his pager but it falls out of his hands from all the twisting and turning. Galeon however still senses his plight and tries to bust out of his chamber, so Kazou has the Triple-decked Flying Carrier launched to let him out.
The Zonder finally exits out of the water and even Mamoru has fallen unconscious. Volfogg immediately drives onto the tracks and gives chase. He transforms to robot mode and uses his Silver Moon to cut the Zonder off from the rest of the coaster; however it manages to grab Mamoru then merges with the track to form EI-13. It moves out into the sea just as Mamoru wakes up. Mamoru and Volfogg spot Galeon charging towards them at full speed. It resists a barrage of needles fired by EI-13 before biting off the arm holding Mamoru. Galeon deposits Mamoru on the shore just as EI-13 traps it with its body. Taiga receives the emergency dispatch on his pager and announces the Zonder attack to the congress, saying that they must move out immediately. The group returns to 3G headquarters with HyoRyu and EnRyu while Guy summons the Gao machines and heads to Okinawa. Volfogg uses his Silver Cross to cut off EI-13 head and free Galeon, who trashes the rest of its serpentine body. Before they can evacuate Mamoru however, EI-13 quickly regenerates into a new two legged body and knocks Volfogg aside. Before it can attack again, it’s impaled by the DrillGao and Guy uses the distraction to form GaiGar. EI-13 catches Guy with an energy snare but Volfogg puts up a smokescreen and cuts him loose. He then uses his Projection Beam to bait EI-13 into attacking a hologram of GaiGar, causing it to fall into the sea. Mamoru asks Volfogg who he is and the latter tells Guy to use this chance to perform Final Fusion. Once GaoGaiGar is formed, Guy grapples with EI-13 and punches it back into the sea. He uses Protect Shade to temporarily part the sea water and lunges at EI-13 with his Drill Knee. As the water falls back in, Guy uses Hell and Heaven to extract the core and Volfogg saves Mamoru from the ensuing wave. Mamoru purifies the core while Polonaise curses at his failure. Ai and Isamu come out of the intact mirror house and find the rest of park demolished. Spotting the departing GaoGaiGar, they panic and run towards Mamoru while Volfogg watches from afar.
As shown in the previous episode, the Machine Kings have different priorities. Pizza and Penchinon think that Mamoru is the biggest threat while Polonaise and Primada believe the key to stopping 3G is destroying Galeon. Either way they better start taking Volfogg into account more because he foiled their plans twice now. On the other side, while 3G has been mostly let off the hook as far collateral damage is concerned, it seems the loss of the Isolde particle accelerator wasn’t something they could just shoo under the rug. Though unlike other shows this group of politicians isn’t completely blind to reason, then again they seem perfectly ok with Taiga singlehandedly throwing off his suit to reveal his usual outfit, Hyuuma ripping off his top by flexing and Leo blasting off with rocket skates. Also, if there’s actually a roller coaster that can fly off its track and into an underwater tunnel, I’d totally ride it.