First appearing in the Hitchcock film The Lady Vanishes, Charters & Caldicott is an updated BBC mystery series. The story shows the pair in their retirement. Caldicott lives in the splendid Viceroy Court in Marylebone, whilst Charters is a widower living in a country cottage near Reigate, travelling up to his Pall Mall club on a Green Line bus (hailing it on the street as if it were a taxi). When a young girl is found murdered in Caldicott's flat, Charters and Caldicott forsake their regular Friday lunch and cinema visit to involve themselves in solving the crime...