A brother and sister from the Rhondda Valley in Wales turn to crime to pay their father's debts and release him from prison. They encounter a beautiful but infuriating widow who persuades them to help recover some stolen letters. This leads them into a murder investigation. The trail lead from Cardiff to Scotland via London and Lancashire. This is a tale of mystery, danger, injustice and romance set against the background of the Jacobite rebellion of 1715.