The second sequel to the Sci-Fi Horror classic The Fly, directed by Don Sharp and released in 1965. Unlike the first film and Return of the Fly, there's no Vincent Price in this one and nobody turns into a fly-hybrid.
While driving home, Martin Delambre (George Baker), the grandson of the "turned-into-a-fly" André from the past films, comes across one Patricia Stanley (Carole Gray) running in the night, and gives her a lift since since she barely has any clothes on. They soon fall in love after this little encounter, and he marries her before taking her to his home. Unfortunately for each other, Patricia is an escapee from a mental asylum and Martin and his father Henri (Brian Donlevy) continue the family tradition of dabbling in experimental teleportation devices that have caused several horrifying accidents already.
This film has examples of:
- Body Horror: Nobody turns into a Half-Human Hybrid this time, but teleportation and/or Rapid Aging turns out to have disfiguring effects on those who experience them. If if that wasn't bad enough, the two ill-fated assistants are slain and their corpses teleported to London in turn for Martin to dispose of the bodies...or rather, body because they're both brought back at the same time.
- Broad Strokes: The film presents itself as a continuation of the previous two films, but its backstory is a mix between; only André Delambre from the first film was turned into a fly, and he was turned back into a human the way Philippe was in the second film.
- The End... Or Is It?: The movie ends with the title card "Is This The End?"
- Madwoman in the Attic: On the mansion's grounds are several cells that contain the results of the Delambres's previous experiments, three disfigured people total. One is Judith, Martin's original wife.
- Poor Communication Kills: As Martin prepares to send his father back to England with the teleportation device, his brother Albert tries in vain to tell him to not to do it, since he has destroyed the the machine on his end. Martin ignores him, and their father is lost inbetween.
- Rapid Aging: Martin's "curse" is that the teleportation experiments from the past have left him in a condition that causes him to age rapidly, which he holds back with special pills. When he fails to get his pills in the ending, he is soon reduced to bones.
- Revenge of the Sequel: Also an example of The X of Y.
- Teleporter Accident: Delambres' teleportation experiments have turned several people into disfigured mutants, including two lab assistants and Martin's first wife Judith.
