A sea monster is rampaging around the south seas and the US government asks a French scientist and his apprentice to check the situation out and report back. Not so much that they believe that there’s dragons eating ships, but that ships are going missing and someone needs to figure out what’s going on.
They learn though that it’s not sea monster, but a submarine going around destroying various merchant boats, boats of war, or literally any boat they happen to see on the open waters. As it happens, the scientist, his apprentice, and a harpooner are knocked off their boat and later picked up by the submarine and through a series of wacky adventures, they end up setting off a nuclear weapon on an isolated island, killing hundreds of slavers and military personnel.
Something that struck me as funny, was that they visited a slave island to watch the slaves do work, all so the captain could justify his crusade against the rest of the world. The name of the island? Rura Penthe, which apparently is unique to this Disney adaptation, and later used as the name of a prison planet in Star Trek VI.
There’s some extremely unfortunate depiction of some native island people, but other than this, for the most part the movie still holds up.
