Martin Durnley (Hywel Bennett) is a surly recluse of extraordinary cunning. After meeting an attractive young student, Susan Harper (Hayley Mills), Martin hatches an elaborate plan to charm his way into her life. To appeal to Susan’s nurturing instincts he adopts an alternate personality, Georgie, a simple, mentally challenged man-child. This devious deception sets in motion an unsettling tale of deadly obsession and frenzied murder!