Interpol launches an investigation into the incident. With the help of marine biologist Akira Ichinose, they trace Titanosaurus to a reclusive, mad scientist named Shinzô Mafune, who wants to destroy mankind. While the group is visiting the scientist's old home, they meet Mafune's daughter, Katsura, who claims her father is dead and that she burned his notes about Titanosaurus at his request. Unbeknownst to Interpol, the living Mafune is visited by Tsuda, aide to the Simeon leader Mugal, who is leading a project to rebuild Mechagodzilla. Mugal offers the Simeons' services to Mafune so that their respective monsters will wipe out mankind and allow them to rebuild the world for themselves.