Taiki lives with his mother and sister. His father works in far away Hokkaido, and is not always home. Taiki is first seen in the film fighting with his sister over a book. The next day, when Taiki awakens, he finds that his sister has developed supernatural powers (due to Belvera's influence) which she uses to harm Taiki. Taiki is chased out of his home, and is forced to hide in a tree until the Elias come to his aid. The Elias and Taiki fight off Belvera, but trash their home in the process. after the Elias explain the importance of the Seal of Elias, Taiki's mother takes Taiki and his sister to Hokkaido to try and place the seal back on the shrine before the monster inside escapes.
Desghidorah escapes from the shrine and begins to destroy Hokkaido, leaving the Gotos and the Elias to watch as the old and weak Mothra fights to stop it. As the fight progresses, The Elias explain much about Mothra and her life cycle to Taiki and his family. Taiki and his family are sent to Hospital after Mothra is defeated. Taiki almost immediately leaves the Hospital after the larval Mothra Leo makes his way to Hokkaido. After Mothra Leo defeats Desghidorah, Taiki and Wakaba are allowed to ride on Mothra Leo's back.