William (Richard Derr) is washed up on a remote island in the Pacific after his cargo ship sinks. He is rescued by Dr Girard (Frances Lederer) and his comely wife Frances (Greta Thyssen). Girard is conducting some kind of strange medical experiments on the island, and there is a beast loose which has killed enough natives that they have fled. However, the beast is not a natural creation but a big cat which Girard is trying to turn into a man.
Despite Frances and William's pleas to leave the island, Girard doggedly continues his experiments with the man-cat (Flory Carlos). However, the creature has developed a fascination for Frances (natch) and is also becoming harder and harder to control...
A story based on a HG Wells tale, and is fine enough though lacks much in the way of action. Much of the film is spent waiting around for something to happen, we really only see the man-cat in the final few minutes, though it really isn't worth the wait. One interesting gimmick is the inclusion of an annoying bell in the soundtrack to warn squeamish viewers to look away if something horrid is about to happen.