Jonathan Aris plays a small yet critical role in this episode. The beautiful Helen Grace (who later guest starred in Rosemary and Thyme) chews the screen, and we're left wondering until the very end who killed Lord Edgware. This episode is the 2nd of two episodes in season 7, four years after season 6. It's not unusual for large gaps between seasons of UK TV series.
Review of Lord Edgware Dies
