In Montreal, Quebec, Canada, scientist André Delambre (David Hedison) is found dead with his head and arm crushed in a hydraulic press. Although his wife Hélène (Patricia Owens) confesses to the crime, she refuses to provide a motive, and begins acting strangely. In particular, she is obsessed with flies, including a supposedly white-headed fly. André's brother, François (Vincent Price), lies and says he caught the white-headed fly; and, thinking he knows the truth, Hélène explains the circumstances surrounding André's death.
Now an adult, 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.
Martin Delambre (Baker) is driving to Montreal one night when he sees a young girl by the name of Patricia Stanley (Gray) running in her underwear. They fall in love and are soon married. However, they both hold secrets: she has recently escaped from a mental asylum; he and his father Henri (Donlevy) are engaged in radical experiments in teleportation, which have already had horrific consequences. Martin also suffers recessive fly genes which cause him to age rapidly and he needs a serum to keep him young.
