In 1757, Moonfleet is a small village near the sea in the south of England. It gets its name from a formerly prominent local family, the Mohunes, whose coat of arms includes a symbol shaped like a capital 'Y'. John Trenchard is an orphan who lives with his aunt, Miss Arnold. Other notable residents are the sexton Mr Ratsey, who is friendly to John; Parson Glennie, the local clergyman who also teaches in the village school; Elzevir Block, the landlord of the local inn, called the Mohune Arms but nicknamed the Why Not? because of its sign with the Mohune 'Y'; and Mr Maskew, the unpopular local magistrate and his beautiful daughter, Grace.