S3, E4: After Mary (Adelaide Kane) receives an urgent message from her ailing mother (guest star Amy Brenneman) about the dire situation in Scotland, she finds herself looking to Francis (Toby Regbo) for aid. Catherine (Megan Follows) finds herself up against Narcisse (Craig Parker) as she fights to become the regent to Charles (guest star Spencer MacPherson). Meanwhile, Elizabeth (Rachel Skarsten) faces continued pressure to wed. Anna Popplewell, Torrance Coombs, Celina Sinden, Charlie Carrick, Jonathan Keltz and Rose Williams star.