The play is set in November 1978: an event in 1968 is referred to as having taken place 10 years earlier; the female lead's editor attends a bonfire party; the tax on her car expires on 31 January 1979; there is a reference to the 30th of the month being a Thursday, which was the case in November 1978.
Like the film "Night of the Demon," this ITV production is only a loose adaptation of the M.R James story, and updates it to the modern world. In this transition, the character of "Dunning", male in the story, becomes a young woman.