According to the courts, Jacko Argyle bludgeoned his mother to death with a poker. Sentenced to life imprisonment, he died behind bars following a bout of pneumonia. Tragically, it was not until two years later that Dr Arthur Calgary came forward with the testimony that could have acquitted Jacko. Worse, the doctor's revelations were about to re-open old wounds in the family, increasing the likelihood that the real murderer would strike again…

Agatha Christie was born in Torquay in 1890 and became, quite simply, the best-selling novelist in history. Her first novel, The Mysterious Affair at Styles, written towards the end of the First World War, introduced us to Hercule Poirot, who was to become the most popular detective in crime fiction since Sherlock Holmes. She is known throughout the world as the Queen of Crime. Her books have sold over a billion copies in the English language and another billion in over 100 foreign languages. She is the author of 80 crime novels and short story collections, 19 plays, and six novels under the name of Mary Westmacott.