In 1978 writer and notorious drama critic Kenneth Tynan’s wife Kathleen devised a speculative account of crime writer Agatha Christie’s mysterious 11-day disappearance in 1926. It was initially proposed as a documentary for the BBC. Christie had died shortly beforehand and her representatives tried to get it stopped. This elegant and suspenseful big-screen account is daubed in an autumnal palette shot by Vittorio Storaro and effectively contained by Michael Apted. Tynan’s story is a pastiche of Christie tropes in a screenplay she co-wrote with Arthur Hopcraft (and her novel came out to chime with the film’s release). Vanessa Redgrave is simply luminous as the shy, introverted writing genius whose husband Archie (Timothy Dalton, Redgrave’s real-life long-term boyfriend) has confronted her about his affair with a woman in his office and his desire to get a divorce in order to marry the other woman. Agatha takes off and arrives in Harrogate, the destination spa town where his mistress is heading with her aunt, in order to plan a ghastly revenge. All of Britain is searching for her. The police don’t like her husband’s reaction and suspect him of murder. In a story where practically everyone is pretending to be someone else, the only occasional downside is the effect of Dustin Hoffman’s pantomime as (fictional) US journalist Wally Stanton, obsessed with tracking down the world-famous woman who had just published The Murder of Roger Ackroyd. Perhaps that’s what they call star power. This lies somewhere between mystery and romance, biography and faction. Christie notoriously refused to address this episode in her autobiography and it was officially attributed to amnaesia. We shall never really know. Now that’s REAL star power.