A young man goes to visit his fiancée and learns that her scientist father, who is wheelchair-bound, has found a meteorite that is emitting mutating radiation. This has caused the plants in his greenhouse to become massive. When the man's wife also becomes affected by this strange force, the father decides to destroy the meteorite, leading to unforeseen consequences. The film was directed by Daniel Haller and written by Jerry Sohl and H.P. Lovecraft, and stars Boris Karloff, Nick Adams, and Freda Jackson.