Astronomers investigate a mysterious meteorite shower in a rural English farm field. The rocks which fell, landed in a V-formation. Dr. Richard Arden, preeminent in the field of extraterrestrial study, is not permitted to accompany his colleagues, including his girlfriend Lee Mason, because he is still recovering from the effects of a recent motor accident. The scientists are summarily taken over by some alien force, and others in the area are dying from a mysterious "crimson plague," which covers their bodies with drops of blood. Temple seems the only person immune to both maladies, so if he can discover the reason for this immunity, he may yet foil the alien plan to take earthlings back to the moon for their own sinister purposes.