Ultraseven: S1 E42 - Ambassador Of The Nonmalt Ultraseven

The "Seahorse" Ocean Base was blown down right in front of Dan and Anne, who were enjoying swimming on their vacation. Shinichi, a boy who predicted the incident, said it was done by Nonmalt, the real aboriginals of the Earth. According to him, humans were invaders who occupied the Earth by expulsing Nonmalt under the sea...