"This is essentially Mothra's mother," the director explained (via ComicBook.com). "The eggs that were laid on the surface were laid by ['The New Empire'] version of Mothra and this film ...

If her sister is to be believed, Mira might hold the key to the rebirth of Mothra and the Earth's return to normalcy. They just have to travel back in time and get its egg from the Jurassic period ...