Recuperating from illness in Chelsea - in 1764, a rural spot - Robert Fairfax expects to be bored. But a chance meeting leads to his involvement with the Mozarts of Salzburg, whose son is the musical prodigy creating a stir throughout Europe. The boy is as inquisitive as any child, and it is this that makes him a witness to the events surrounding a suspicious death. The mystery deepens with the discovery of a girl's murdered body. Perhaps even Fairfax's famed ingenuity cannot solve this puzzle - unless he can garner a crucial clue from the boy whom the world will know as Wolfgang Amadeus Mozart...