"The humans of our Earth fight fire with fire as they begin to create their own counter-measures for Godzilla. Yet the alternate Earth still has more monster surprises in store!"
SPOILER WARNING: This section may contain major plot and/or ending details. Proceed at your own discretion.
As the army of MechaGodzillas flies into battle against Godzilla, Dr. Talbert asks Ridley why she didn't just build one giant MechaGodzilla instead of several smaller ones, stating that Godzilla will just swat the robots away like flies. Ridley states that there is a theoretical backup plan should the MechaGodzillas fail: King Ghidorah's carcass could be salvaged and cybernetically modified to make him into a weapon they could control. Weinstein asks Ridley how long the plan would take, with Ridley stating it's highly theoretical. Believing it is the best option left, Weinstein tells Ridley to go through with the plan and begins recruiting the military's help. While Godzilla battles the MechaGodzillas out at sea, Ridley and a team of divers sneak past him in a boat and dive to the sea floor, where King Ghidorah's body lies. Ridley states that although the beast's central head is gone, its wings are shredded and there is a gaping wound in its chest, it is intact enough to be salvageable. The divers place a giant balloon underneath the carcass and pump it with air, allowing it to float to the surface. Helicopters arrive and attach lines to King Ghidorah's body, then airlift it away while Godzilla is still distracted by the MechaGodzillas. Back at the laboratory, Ms. Yamada and Dr. Talbert await Ridley's return and discuss further options should this plan fail. Talbert morosely states that if this plan doesn't work, they will all die. Talbert receives word from Ridley that King Ghidorah's carcass has arrived at the facility and goes to look at it. Using cranes, scientists fit King Ghidorah's body with robotic parts and convert it into Mecha-King Ghidorah. As Talbert and Ridley stare at the completed cyborg, Talbert tells Ridley to check the polarity, to which she replies she already did. Ridley activates Mecha-King Ghidorah, causing the eyes on its mechanical head to light up. Just then, they hear Godzilla's roar as the monster arrives and tears open the walls of the facility. As the monsters prepare to battle, Talbert tells Ridley to go somewhere safe, but she tells him that she will be fine and that he needs to go check on the interdimensional portal. Talbert kisses Ridley on the cheek and wishes her luck, then runs to the portal, which is powering up on its own and being opened from the other side. When Talbert arrives, Ms. Yamada sees a simple message on a computer screen transmitted from the other Earth, which simply reads "We're so sorry." The portal opens, and through it emerge Rodan, an adult Mothra and two larvae, Biollante, Anguirus, King Caesar and Zilla. Talbert and Yamada then realize the people of the other Earth have doomed them.