In 1962 an elderly Agatha Christie (Anna Massey) is attending a party at the theatre for a decade of The Mousetrap. Questions from journalists spur memories of 25 years ago when as a younger woman (Olivia Williams) attending a psychiatrist (Stephen Boxer) she is hypnotised into recalling why she disappeared four months earlier triggering a police search … Richard Curson Smith’s docudrama is based on the intriguing real-life case of the famous author’s apparent fugue state when she was located at a spa in Harrogate, having signed in under the name of the mother of her husband’s mistress. The title alludes to the means by which the doctor engages with Christie to start the story: as a young girl (Bonnie Wright) whose father’s death changes the family dynamic, particularly when her older sister marries. She has been haunted for years by a mysterious character whom she calls The Gunman and many men of her acquaintance transform into this figure when she is under stress. Her marriage to soldier Archie Christie (Raymond Coulthard) is met with disapproval by her mother, who encourages her to write. Her time nursing wounded soldiers introduces her to Belgian refugees, one of whom inspires Hercule Poirot and her first novel. She has few memories of times when she is happy, the catalysts for unhappiness make her focus on what may have occurred to prompt her flight – her discovery of her husband’s adultery with Nancy Neele, a secretary … The use of photos, pastiche photographic studios and fake home movies and newsreels gives this a patina of realism which is visually impressive. This is territory previously explored by the film Agatha and Kathleen Tynan’s book, and more recently in a faction novel by Andrew Wilson. Williams gets the lion’s share of the scenes, as a morose young woman who must confront her husband’s extra-marital liaison and his wish to end their union. Even her little daughter says it’s her mother that’s the problem. The older Christie is wiser and happier following a long marriage to a younger man, archaeologist Max Mallowan (Bertie Carvel) whose work on sites in Syria and Iraq literally takes Christie out of herself and England and also inspires some of her best books which she then produces annually. There’s a terrific scene when she comes up with the idea for The Murder of Roger Ackroyd which is the book that made her know she was good. There are some technical issues with the sound mixing (you can hardly hear Massey, and some dialogue is drowned out with incidental music) but it’s a thorough and thoughtful account of an episode that’s as mysterious as any of Christie’s novels, supplying psychology to the central character in a way that the Queen of Crime disdained.