Receiving an invitation (from Lord Cavendish-Smith), Sherlock Holmes and Dr John Watson attend a party in honour Lavinia Bromsby, daughter of wealthy industrialist (and party host) Sir Melvyn Bromsby. Things then take a sharp turn when, in the midst of a speech, Sir Melvyn is shot by some unseen perpetrator hidden in the room. All suspicion (and initial evidence) points to Lavinia, the daughter. Determined to get to the bottom of this, Sherlock Holmes takes the case. But what seems to be a simple murder will take the pair through the long and complicated history of Sir Bromsby's estate.