An expedition at the end of the nineteenth century drops an improbable bathysphere into the Carribean to look for treasure.
The crew mutiny and the scientists end up under the sea. Where is this ? they say, it's Atlantis (Malta actually).
Taken by guards to the third city, whose helmets are in the sci-fi tradition, completely unfunctional, one of them meets the Atlantans, who are space travellers with special powers but use mediaeval cannons against giant lizards, and lose.
Released a year after Star Wars, indeed.
Review of Warlords of the Deep
