The Mary of the title refers to Mary Queen of Scots, and this play is an inquisition into her moral virtues, although she never appears on stage to defend herself and judgment is cast in her silence.
Three characters argue the case for or against her instead: Agnes (Rona Morison), a maid at Holyrood Palace who condemns Mary Stuart’s motives and Catholicism; Thompson (Brian Vernel), a servant with self-interested allegiances; and its central figure, Sir James Melville (Douglas Henshall), the Queen’s most loyal courtier who stands alone as the nation turns against her.
