Ray Milland plays Dr. James Xavier a brilliant scientist who understands that the human eye only perceives a tenth of the entire visual spectrum. Through his experiments he develops an eye drop that allows a monkey to see through hard material and his gal-pal Dr. Diane Fairfax (Diana Van der Vlis) is astounded at the discovery. Xavier turns to his friend Dr. Sam Brant (Harold J. Stone) to aid him in administering the drug on himself to record the details first hand, but Brant doesnt want to because too much is still unknown about the drug. Xavier goes forward with his plans and discovers a wealth of new visual abilities he didnt posses before.
His ability to see through material prevents a miss-diagnosed surgery but puts him at odds with the attending physician at his hospital. Brant tries to prevent Xavier from continuing the drug because of the physical damage to his system. In the midst of an argument Xavier accidentally causes the death of Brant and Diane convinces Xavier to flee until he can pull himself together and explain what happened. Xavier drops out of sight until Diane tracks him down and discovers that by continually using the vision drug Xavier has developed a sensitivity that has caused shocking changes in the doctors persona.
As the police close in and crosses paths with a religious preacher the doctor takes some actions that have drastic aftereffects..