In foggy London Dr Jekyll experiments on newly deceased women determined to discover an elixir for immortal life. Success enables his spectacular transformation into the beautiful but psychotic Sister Hyde who stalks the dark alleys of Whitechapel for young, innocent, female victims, ensuring continuation of the bloodstained research. With each transformation Sister Hyde becomes the more dominant personality, determined to eventually suppress the frail, ineffectual Dr Jekyll forever.

The great hypnotist Professor Montserrat has developed a technique for controlling the minds, and sharing the sensations, of his subjects. He and his wife Estelle test the technique on Mike Roscoe, and enjoy ‘being’ the younger man. But Estelle soon grows to love the power of controlling Roscoe, and the vicarious pleasures that provides. How far will she go, and can the Professor restrain her in time?