A young man visits his fiancé's estate to discover that her wheelchair-bound scientist father has discovered a meteorite that emits mutating radiation rays that have turned the plants in his greenhouse to giants. When his own wife falls victim to this mysterious power, the old man takes it upon himself to destroy the glowing object with disastrous results.
Boris Karloff
as Nahum Witley
Nick Adams
as Stephen Reinhart
Suzan Farmer
as Susan Witley
Freda Jackson
as Letitia Witley
Terence de Marney
as Merwyn
Patrick Magee
as Dr. Henderson
Sheila Raynor
as Miss Bailey
Harold Goodwin
as Taxi Driver
Paul Farrell
as Jason
Sydney Bromley
as Pierce
Billy Milton
as Henry
Leslie Dwyer
as Potter
