After his father dies of a heart attack, Ian Blackie finds an old box full of a bizarre assortment of papers in the attic of his parents' home. Hidden amongst the papers are some mysterious personal mementos belonging to General Alexander Ballantine, his father's old school friend, recently killed by an IRA bomb.

Ian soon realises that his father had been conducting his own investigation into Ballantine's murder, refusing to believe the IRA angle. Intrigued, Ian decides to follow the clues he has left, which leads him to the Tartan Conspiracy and a race to prevent the murder of the Queen.