In mid-1992, following the events of "Godzilla vs. King Ghidorah", a meteoroid crashes in the Ogasawara Trench and awakens Godzilla. Six months later, explorer Takuya Fujito is detained after stealing an ancient artifact. Later, a representative of the Japanese Prime Minister offers to have Takuya's charges dropped if he explores Infant Island with his ex-wife, Masako Tezuka and Kenji Ando, the secretary of the rapacious Marutomo company. After the trio arrives on the island, they find a cave containing a depiction of two giant insects in battle. Further exploration leads them to a giant egg and a pair of diminutive humanoids called Cosmos, who identify the egg as belonging to Mothra.