The film takes place in the present, when two newlywed couples are enjoying a charter boat cruise through the Caribbean. Passing through a bizarre storm, they emerge off the shore of the mysterious island of Caprona.

The island, which seems to exist within a time void inside the Bermuda Triangle, is full of anachronistic inhabitants, including dinosaurs and prehistoric mammals and the crew of a stranded German U-Boat. The newlyweds, along with the charter boat's captain and the Germans, must battle a variety of obstacles to escape the island and get back to their own time.