Ebirah, Horror of the Deep (1966)

Ryota is a young man searching for his missing brother, Yata. He joins up with his friends Nita and Ichino as they sneak on board a ship supposedly belonging to Yoshimura, a career criminal escaping from the authorities. As the group sets sail, they are caught in a storm and attacked by a monstrous crustacean. Shipwrecked on Letchi Island, they find that the natives of Mothra's Infant Island have been enslaved by a terrorist organization called the Red Bamboo. The terrorists force the natives to process a juice that holds off the monster crustacean, Ebirah. The men meet up with a native escapee named Daiyo as they stumble upon Godzilla sleeping on the island. The groups sets up a plan to awaken Godzilla to defeat the Red Bamboo terrorists and liberate the natives.