"A scientist has created a portal to another dimension -- one where monsters rule supreme! A terrifying expedition begins into a world where hope has died and Godzilla is the unrivaled King of the Monsters. But what happens when a baby kaiju hitches a ride back to the original, monster-less dimension?"
SPOILER WARNING: This section may contain major plot and/or ending details. Proceed at your own discretion.
In the laboratory of Dr. Eli Talbert, his assistant Ridley informs him that the interdimensional portal they had been working on is finally completed. Just then, Talbert's employer Ms. Yamada enters the laboratory and tells Talbert to turn on the portal. Talbert warns Ms. Yamada that the portal is a completely untested technology that requires further testing, but she tells him that his only job was to build the portal, and that job is now completed. Talbert activates the portal, and Ms. Yamada and her bodyguards go through, with Talbert close behind. On the other side of the portal, they find themselves in the ruins of a city. As they wander through the ruins, the bodyguards notice something fly past them and open fire at it. One bodyguard walks towards it, only for the creature to reveal itself as a tiny Rodan, who kills the bodyguard with its uranium heat beam. The group suddenly hears a voice ordering them to return to a shelter as Kiryu arrives and attacks the Rodan. As Kiryu blasts the Rodan with a laser beam, several more Rodans descend and swarm the machine. The humans start to run away, but one Rodan catches up with them. Before the Rodan can carry off one of the bodyguards, it is blasted by a soldier wielding a laser gun. The soldier and the rest of his men load Talbert, Yamada and the bodyguards onto a truck and drive away. The soldier chastises Talbert and Ms. Yamada for wandering in the area most populated by giant monsters. Talbert asks what happened to the city, only for the soldier to incredulously ask if he is kidding. Ms. Yamada explains that they are "visitors" to the city, and that their transport broke down. The soldier then explains that the giant monsters began appearing about ten years ago and terrorized the Earth, only for a much more powerful monster to appear and end their reign of terror. He orders the shades on the truck to be lowered, and shows them the monster in question: Godzilla. The soldier says that Godzilla keeps the other monsters in check and prevents them from growing to full size, and that he and his men do whatever it takes to keep Godzilla happy. Talbert tells them to turn the truck around, and one of Ms. Yamada's men holds the soldier at gunpoint. The truck drops them off, near a battle between two Rodans and two Mothra larvae. As they run back to the portal, they are pursued by a huge three-headed dragon, which a bodyguard says is called King Ghidorah by the soldiers. Talbert, Ms. Yamada and her remaining bodyguards go through the portal, but before it can close King Ghidorah travels through it as well.