Vincent Price as Francois Delambre
Brett Halsey as Philippe Delambre
David Frankham as Ronald Holmes / Alan Hinds
John Sutton as Inspector Beecham
Dan Seymour as Max Barthold
Danielle De Metz as Cecile Bonnard
Jack Daly as Granville
Janine Grandel as Mme. Bonnard
Michael Mark as Gaston
Richard Flato as Sgt. Dubois
Barry Bernard as Lt. MacLish
Pat O'Hara as Inspector Evans
Ed Wolff as The Fly
Return of the Fly is the first sequel to the 1958 horror film The Fly. It was released in 1959, and directed by Edward Bernds. Unlike the preceding film, Return of the Fly was shot in black and white. The film was followed by another sequel in 1965, Curse of the Fly.
It was intended that Herbert Marshall reprise his role as the police inspector, but due to illness he was replaced by John Sutton.
Vincent Price was the only returning cast member from the previous film.
Phillipe Delambre (Brett Halsey) is determined to vindicate his father by successfully completing the experiment he had worked on. His uncle Francois (Vincent Price) refuses to help. Phillipe hires Alan Hines from Delambre Frere and uses his own finances, but the funds run out before the equipment is complete. When Phillipe threatens to sell his half of Delambre Frere, Francois relents and funds the completion. After some adjustments, they use the transporter to "store" and later re-materialize test animals.
Alan Hines turns out to be Ronald Holmes, an industrial spy. Holmes tries to sell the secrets to a shadowy cohort named Max. Before Holmes can get away with the papers, a British agent confronts him. Holmes knocks him out and uses the transporter to "store" the body. When rematerialized, the agent has the paws of a guinea pig that had been disintegrated earlier, and the guinea pig has human hands. Holmes kills the rodent and puts the dead agent in his car, which he sends into the Saint Lawrence River.
Phillipe confronts Holmes about all the oddities, with a fight ensuing and Phillipe being knocked out. Holmes hides Phillipe the same way he did the agent, but in a twist of malice he catches a fly and adds it to the transporter with him. Francois re-materializes Phillipe, but with a fly head, arm and leg while the fly has his head, arm and leg, becoming "PhillipeFly". PhillipeFly runs into the night, tracking down and killing Max. He waits for Holmes to arrive and kills him, too. PhillipeFly returns home, where Inspector Beecham has found and captured the PhillipeFly. Both are placed in the device together and successfully reintegrated.