The protagonist is a young woman, Joan Prats suffering from agnosia, a strange, primary visual disease that is one of the neuropsychological disorders of perception. Although her eyes and ears are in perfect condition, her brain is not able to correctly interpret the stimuli it receives. Joan is the only person to know an industrial secret left behind by her late father and becomes the victim of a sinister plan to extract this information. Her captors plan to use her sensory condition to help extract the information that they so desperately want.

Once again tampering with mother nature to disastrous results, Dr. Herbert West continues his research while serving time in a maximum security prison for his previous exploits. West’s limited prison-cell experiments are suddenly interrupted by the arrival of a new prison doctor and the brother of the girl who suffered from West’s experiments 13 years earlier.