When the sleepy town of Weyharrow is enveloped by a mysterious fog, the inhabitants find themselves behaving in strange and dangerous ways. Dr Steven Glaze, a young probationary GP, prescribes a most unorthodox treatment for arthritis; the vicar proclaims in morning service that the villagers are in the hands of the devil; and Phyllis Knabbe tragically commits suicide. Throughout the village peopl...