She is first seen approaching her incarcerated ex-husband Takuya Fujita with a government official to offer him a chance out of his fifteen year sentence in exchange for alimony. She accompanies him on their journey to Infant Island to make sure he does not run away. She and her group eventually happen across a Mothra egg and the Cosmos. It is decided that they will take them back to Japan, but partway through the journey the egg hatches and they are forced to leave it. Back in town, she reunites with her and Fujita's daughter at a subway station, but finds that Fujita and the Cosmos are missing. She and their daughter rack him down in time for their daughter to convince him that what he has been doing is wrong. The Cosmos intervene with the rampaging larval Mothra to send it away. Mothra eventually Metamorphosis into her Imago form to combat Battra and Godzilla. Masako is present to watch the final battle unfold.