Godzilla vs. the Sea Monster (1966)
Some teenagers want to obtain a boat to find a brother. When they look around a boat without permission, they find a thief who takes them on his escape. They are caught in a storm and arrive at Letchi Island where natives of Infant Island have been enslaved by the terrorist organisation Red Bamboo. Red Bamboo runs a heavy water factory to process a juice which holds off the monster, Ebirah, which otherwise traps them on the island. The young men meet beautiful but tough Daiyo and wake up Godzilla to put an end to the Red Bamboo.