Tommy and Tuppence Beresford have just become the proud owners of an old house in an English village. Along with the property, they have inherited some worthless bric-a-brac, including a collection of antique books. While rustling through a copy of 'The Black Arrow', Tuppence comes upon a series of apparently random underlinings.
However, when she writes down the letters, they spell out a very disturbing message: Mary-Jordan-did-not-die-naturally. And sixty years after their first murder, Mary Jordan's enemies are still ready to kill . . .