Oliver is a middle-aged lecturer in Comparative Religion, with a passion for trivia, crosswords, and anagrams, and a very strange sense of humour. Having been fired from the University of the Rhondda Valley, and with no family ties, he decides to set off on a quest to find 'Aristotle', a setter of crosswords. He teams up with WPC Diane Priest, who has just been suspended for asking too many questions about a local murder that seems to implicate the Chief Constable. Pursued by 'The Man with No Name', the unlikely duo visit Shrewsbury, North Yorkshire, Durham, Hadrian's Wall, and Kirkleven in the Scottish highlands on their journey to find 'Aristotle' in the Orkney Isles.
