Azusa was a biology researcher working at the Japanese National Life Sciences Institute in Kyoto under Professor Hiroshi Omae. Azusa accompanied Professor Omae on an expedition to the remote and heavily irradiated Adonoa Island in the Bering Sea, where a team of Russian petroleum drillers had discovered a seemingly perfectly-intact egg in a pteranodon nest. The team placed the egg in a tent and prepared to take it back to Kyoto for study. However, the giant irradiated pteranodon Rodan arrived and tried to take the egg back from the scientists. Azusa and the others ran from Rodan, but were stopped at the end of a cliff overlooking the ocean. Suddenly, the ocean flashed and Godzilla rose from the water. Godzilla came ashore and battled Rodan, allowing the scientists to escape the island with the egg. Azusa was put in charge of monitoring the egg at the institute, where the creature inside imprinted on her as its mother. Azusa was attempting to study a strange prehistoric fern that was found growing on the egg, but was interrupted when Kazuma Aoki, a self-proclaimed "pteranodon enthusiast," entered the lab and began taking pictures. Azusa forced Kazuma to leave, but not before he had stolen a sample of the fern. Kazuma had given the fern to Miki Saegusa, who brought it to the biotechnics institute to measure its psychic energy. Workers at the institute isolated a bizarre melody from the plant's energy, and presented it to Professor Omae. While the melody was being played, the creature inside the egg was granted an intake of power from the music and hatched. Azusa immediately called Omae, who arrived with Miki and Kazuma to see what had hatched from the egg, a baby Godzillasaurus. The infant was gentle towards Azusa, believing her to be his mother. Azusa no longer was afraid of the creature, and began calling it "Baby." Miki suddenly sensed that Godzilla had made landfall in Japan and was approaching Kyoto. Realizing that Godzilla was likely coming to collect Baby, Azusa and the others quickly brought him to the basement of the institute. When Godzilla arrived, he destroyed the upper floors of the institute and roared in frustration before finally leaving. Baby Godzilla was then transferred to a G-Force facility, with Azusa serving as his caretaker. G-Force had actually been studying Baby Godzilla's anatomy in order to discover a potential weakness in Godzilla, and discovered that Godzillasauruses possessed a secondary brain in their pelvic region. When Azusa learned of G-Force's plan to use Baby Godzilla as a decoy to lure Godzilla to the Ogasawara Islands and kill him with MechaGodzilla, she was outraged and begged the U.N.G.C.C. secretary, Takayuki Segawa, not to go through with the plan, though he assured her they had no choice. When Baby Godzilla was being transferred to a container that would carry him to the Islands, Azusa saw his eyes glow red, signifying that he was afraid. Azusa ran into the container, and insisted that she accompany Baby. Commander Aso agreed, and the container was sealed.
While Baby and Azusa were being taken to the Ogasawara Islands, Rodan, now revived as Fire Rodan, destroyed the helicopter carrying the container and took it to the center of a city. Rodan attempted to break the container open with his beak, but was interrupted by the arrival of MechaGodzilla and the Garuda. MechaGodzilla and Garuda were successful in luring Rodan away from the container, and a group of G-Force soldiers accompanied by Professor Omae arrived to try and free Azusa and Baby. After Godzilla had arrived and was paralyzed by Super MechaGodzilla, Baby Godzilla smashed himself free of the container and cried out, drawing the attention of the wounded Rodan, who sacrificed his life to heal Godzilla. After Godzilla had destroyed MechaGodzilla, Baby attempted to follow Azusa back to a G-Force helicopter. Azusa tearfully told Baby that he had to go with Godzilla, as he did not belong with humans. As Azusa climbed into the helicopter, she turned to see Baby still tugging on her shirt, with tears welling in his eyes. Azusa hugged Baby one last time, wished him farewell, and then left in the chopper. Azusa contacted Miki Saegusa and asked her to use telepathy to make Baby understand that he needed to go with Godzilla. Miki obliged, and Baby accompanied his new adoptive father out to sea.