After Helene Delembre (Patricia Owens) had been seen at a murder scene of her husband, Andre Delambre (Al Hedison), she has been accused of murder. As she admits to killing her husband to her brother in law, Francois Delambre (Vincent Price), but she refuses to say why she did it.
Francois finds a to his astonishment the unbelievable science experiments conducted by Andre. He had created by teleportation device he intended to help all of mankind but when he tested it on himself something went horribly wrong. After many failures and successes with his machine he finally test the device on himself. Unknown to him a common housefly was with him in the teleporter and has cause him to become a creature with the features of man and fly. Helene also tells of her own challenges of try to help him throughout his ordeal.
Francois meanwhile tries to find any evidence that will prove these events happened and along with Helene's innocence to the local police.
The film was directed by Kurt Neumann and was shot in CinemaScope with Terror-Color by De Luxe. Released by 20th Century Fox.
Two sequels were made The Return of the Fly and The Curse of the Fly. Also it was remade by David Cronenberg in 1986.
This is the theatrical trailer without watermarks.