After the radioactive storms on Sollgel Island transformed the man-sized Kamacuras to giants, the world was stunned to see the insects descend on a small mountain and unearth a mammoth egg. The mantis creatures immediately smashed the shell, revealing within an infant Godzilla. The ravenous insects were about to gorge on the helpless Minilla, when Godzilla stepped in, blasting the creatures into full retreat. Then, in an act of benevolent heart, Godzilla adopted the baby as his own. Teaching the growing Minilla how to belch its fires and survive on the harsh lands. However, their survival was put to the test when the gigantic black spider, Kumonga, crawled from the brush. Only under the combined flames of each monster did they burn the vile existence of the arachnid away.
Following the defeat of Kumonga, the scientists of the island caused a blizzard to hit the once tropical shores, thereby forcing Godzilla and Minilla into hibernation. After their forced hibernation, it's assumed that the monsters found a new home in the South Pacific, a place dubbed Monster Island. It is here that children of Japan dreamed of. Some even imagining themselves to be friends with the little creature, and help see it through battles with a cat like ogre, Gabara. However, following the island's decimation in 1973, it's assumed that the monsters again relocated, this time to a forced habitation established by humanity on the Ogasawara Island chain. To a place called Monster Land.
Later, near the dawn of the 21st century, Minilla, along with the rest of the Monster Land's inhabitants, were taken over and controlled by an invading alien race. The Kilaakian used the monsters to carry out tactical strikes humanity, but were soon foiled. Not even their last ditch monster, King Ghidorah, could turn the tide, as Minilla helped in the defeat of the space monster once and for all.
As multitudes of malicious monsters began to appear across the globe, an odd creature appeared at the summit of Mt. Fuji. This was a small monster, one that had no interest in destruction. Even still, those who did not understand it considered it a menace. A hunter began to load his firearm and aim it at the defenseless creature, but right before he pulled the trigger, his grandson intervened and pleaded with the old man to spare the young creature's life. The hunter hesitantly agreed and allowed the strange mutation to live.
Shortly thereafter, it was discovered that the monsters were released upon the world as part of a full-scale alien invasion! The belligerent extra terrestrial race, known as the Xiliens, unleashed the terrible titans on the human race once more. The boy, his grandfather, and the small monster, now named Minilla, left the summit of Mt. Fuji, deeming the area unsafe. Meanwhile, Godzilla pounded his way through the Xilien resistance, having defeated Zilla, Kumonga, and Kamacuras. He approached Mt. Fuji, and successfully repelled the combined forces of Rodan, Anguirus, and King Caesar. Minilla was being transported nearby, and it began to approach Godzilla. As Godzilla defeated his foes, Minilla attempted to fire an atomic ray in celebration, but only managed to muster a rather insignificant atomic ring. Disappointed, he tried again and began to charge his blast. Though the beam didn't fire, the juvenile theropod grew to an incredible height. Unfortunately, Godzilla took his leave, and it would be some time before Minilla would see this monster, whom he oddly admired, once more…
Following the defeat of the Xiliens and Keizer Ghidorah, Godzilla forced his old enemy, the Gotengo, to the ground. As the massive monster began to walk toward the disabled craft in order to finally eradicate his old nemesis, Minilla intervened, much like the young boy who saved him. He pleaded with Godzilla to spare the ship, and the beast appeared to listen to him. This communication proved that Minilla was in fact the son of Godzilla, and in response to his son’s pleas, Godzilla agreed to spare the Gotengo. The two creatures took their leave as Minilla fired a full atomic ray into the distance. As they swam into the sunset, one thing was certain: Godzilla's legacy would never end.