Mary Stuart's (Saoirse Ronan's) attempt to overthrow her cousin Elizabeth I (Margot Robbie), Queen of England, finds her condemned to years of imprisonment before facing execution.Mary Stuart's (Saoirse Ronan's) attempt to overthrow her cousin Elizabeth I (Margot Robbie), Queen of England, finds her condemned to years of imprisonment before facing execution.Mary Stuart's (Saoirse Ronan's) attempt to overthrow her cousin Elizabeth I (Margot Robbie), Queen of England, finds her condemned to years of imprisonment before facing execution.