A little boy named Alwyn Jones comes to the precinct to tell the constables that he witnessed a crime. Inspector Murdoch decides to indulge him by accompanying him where the crime happened. Alwyn swears he saw a giant knight and heard a gun being discharged but Murdoch sees nothing. He brings the boy back home and makes the acquaintance of his mother, Enid.
Murdoch must investigate the murder of Ezra Dolomore, a scientist. When Terrence Meyers is spotted near the body, Murdoch believes there is more than meets the eye.