As the Pliers are repaired, Mikoto and Leo oversee the construction of a new robot. Leo says that they’ll be done assembling the new system soon, but they still have problems with the AI system. Hyuuma chimes in that there’s no problem because the AI is based on his personality. Mikoto asks if this is true and Leo replies that they had to copy human thought patterns because they didn’t have time to properly develop an AI like the other 3G robots. This new robot, Goldymarg, will be GaoGaiGar’s backup. At the Goteiyama Science Center, a media event is held to demonstrate a gravity control system developed by Professor Akiko Hirata. Akiko starts the test to levitate a whole truck, but nothing happens, so she makes up an excuse and tells everyone to leave while the attending Leo and Swan look on. Back in her lab, Akiko pours over her research and says her theory should have been perfect. Polonaise and Primada appear, saying that she’s just the person they’re looking for before giving her a Zonder crystal. Hana frets over her weight because they have a physical examination at school today. All over G-Island road vehicles and subway trains start getting crushed by an unknown force. Mamoru senses a Zonder as he heads out to school. 3G tracks the Zonder underground and find its source to be the science center. HyoRyu and EnRyu grab their Pencil Launchers and head out. In the subway tunnels, rescue workers pull people out of the wrecked train. HyoRyu and EnRyu fire an adhesive at the roof of the tunnel just before it starts collapsing. Guy arrives in the DrillGao and spots a tunnel which 3G suspects was made by the Zonder. Volfogg finds the Zonder but suddenly sinks into the ground before he can contact the main order room. At school, Hana refuses to eat her lunch and Reiko figures she must be worried about her weight. Her gloating doesn’t last long as soon everyone feels too heavy to stand up anymore. A huge gravity wave overtakes the entire city and the tunnel with the 3G Mobile Corps in it collapses.
Mikoto can’t get in touch with Guy, and the rest of the 3G staff succumbs to the abnormal gravity. Leo and Entouji note that at this rate everyone will be crushed flat and G-Island itself will sink. Volfogg manages to get a message through that the Zonder EI-20 is the one controlling the gravity. Down in the 3G metal locker room where Goldymarg is stored, the electric shock from a loose wire activates him. He breaks out of his restraints and manages to move through the gravity wave thanks to his immense strength. Hyuuma asks Goldymarg where he’s going, and the latter replies that now’s not the time to be sitting around before wrenching open the locker doors. Hyuuma reports to the main order room and Taiga says Goldymarg is their only hope now. Polonaise and Primada stand on top of the Bay Tower and survey the chaos. They spot Goldymarg busting out of the tower and heading towards EI-20. EI-20 hits him with an even stronger gravity wave but Goldymarg continues to push through, so it reverses the gravity to repeatedly lift and smash him into the ground. Finally fed up, Goldymarg fires his Marg Cannon into the air, and the gravity bends the beam towards the Bay Tower where it hits the observatory. The observatory rolls off the side of the tower and slams right into EI-20, disabling its gravity control system. EI-20 attacks Goldymarg with its tentacles, but HyoRyu and EnRyu arrive to destroy them. They continue firing at EI-20 but it erects a barrier and tries to regenerate its gravity control system. Big Volfogg uses his Melting Siren to disable the barrier and renders it vulnerable again. Guy performs Final Fusion and asks Goldymarg to show the Zonder their ultimate attack. GaoGaiGar detaches his right arm and combines with Goldymarg, who has transformed into a large arm, the Marg Hand, used to hold the Goldion Hammer. Guy performs Hammer Hell and Heaven by slamming an energy nail into EI-20 and pulling it out along with the core before disintegrating the main body with the hammer. Mamoru arrives to purify the core. Later, Leo laments the destruction of his observatory and Hyuuma tells him that Goldymarg will help repair it. Goldymarg refuses and states his only job is to enable the use of the Goldion Hammer. He and Hyuuma bicker back and forth while Mikoto expresses her happiness that Guy can fight without any worries now.
3G gets its newest addition in the form of the immensely powerful Goldymarg, a robot whose sole purpose is to allow GaoGaiGar to wield the Goldion Hammer without any repercussions. Unfortunately, since he’s based on Hyuuma he’s not quite as friendly as the other robots and has quite an ego. I also wonder though how GaoGaiGar’s small upper arm joint can handle such a huge chunk of metal without snapping from the sheer weight. The Zonders are gonna have to step up their game even further if they ever hope to stand a chance against 3G now. On another note, I know this isn’t the first time they tried to flaunt Swan for fanservice, but why is she wearing such a skimpy outfit in the middle of a scientific demonstration covered by the media? Were she and Leo just taking a walk and randomly decided to drop in?