Bates plays the titular Oliver, a keen word-game enthusiast and lecturer in comparative religion. After his teaching post is made redundant, he resolves to make use of his new wealth of free time by going to visit his favourite crossword compiler, 'Aristotle', with whom he has corresponded but whom he has never met. When he arrives, however, he finds Aristotle's house has been ransacked and its occupant has departed for parts unknown, and he sets out to discover why.