Harry Benson is prone to violent, uncontrollable seizures and is under police guard after attacking two people. Dr. Roger McPherson, head of the prestigious Neuropsychiatric Research Unit at University Hospital in Los Angeles, is convinced he can cure Benson through a procedure called Stage Three. During this highly specialized experimental surgery, electrodes will be placed in the patient's brain, sending monitored, soothing pulses to its pleasure canyons. But though the operation is a success, there is an unforeseen development. Benson learns how to control the pulses and is increasing their frequency. He escapes—a homicidal maniac loose in the city—and nothing will stop his murderous rampages or impede his deadly agenda . . .