The Taint

The Tardis lands in 1963, and soon the Doctor and Sam become involved in the psychological experiments being performed by Charles Roley on former sufferers of mental illness—he is probing the psyches of six people who believed they've been possessed by the devil. While the Doctor is horrified to learn the full extent of the side-effects brought into being by Roley's research, Sam heads off to experience the swinging London of her parents' youth. Instead she finds deadly danger at the hands of a sinister half-man half-robot double act whose agenda is inextricably linked to Roley's test subjects.