The Dauphin's widow weds a lord and is executed for plotting against the queen.
| Actor | Role |
|---|---|
 Fay ComptonMary Stuart | Mary Stuart |
 Gerald AmesBothwell | Bothwell |
 Ivan SamsonLord Dudley | Lord Dudley |
 John StuartGeorge Douglas | George Douglas |
| EEllen ComptonQueen Elizabeth | Queen Elizabeth |
| LLionel d'AragonMoray | Moray |
 Harvey BrabanRuthven | Ruthven |
 Irene RookeCatherine de Medici | Catherine de Medici |
| DDonald MacardleFrancis II | Francis II |
 René MaupréRizzio | Rizzio |
| EErnest A. DouglasCardinal | Cardinal |
| SSydney SeawardLord Douglas | Lord Douglas |
| EEdward SorleyJohn Knox | John Knox |
 Betty FaireMary Beaton | Mary Beaton |
 Dorothy FaneMary Beaton | Mary Beaton |
| NNancy KenyonMary Fleming | Mary Fleming |
| JJulie Hartley-MilburnMary Seaton | Mary Seaton |
 Basil RathboneUndetermined Subordinate Role | Undetermined Subordinate Role |
 Jack CardiffNot listed | Not listed |