The drama is set to intensify in "Reign" as it barrels towards its season finale. The previous episode saw the rise of Mary as the Queen of Scotland. She also made it clear to Francis that she will always pick Scotland over France. The new episode promises to heighten the conflict between Francis and Mary, as Mary asserts herself.
The Episode 18 of "Reign" is titled "No Exit." The episode features the arrival of Mary's brother, James. He wants Mary to come home to Scotland. The synopsis of the episode suggests that he is asking his sister's return to Scotland, with an ulterior motive.
The arrival of James and his invitation make Francis suspicious. He discovers a plot that would destroy Mary. This might make Mary wary about her brother and her mother, Marie de Guise. But, it is also likely to cause a rift between Mary and Francis. Mary, the Queen of Scotland, would want to confront her country's enemies by leading from the front, while Francis may want to be her protective shield.
In the preview of the episode, Mary can be seen telling Francis, "you love a girl, you don't love a Queen and you wouldn't allow me to be one."
Meanwhile, King Henry's condition deteriorates. Francis fears that since his father is mad, France may fall apart. Seeing King Henry's mental illness, Penelope is likely to take the reins of his powers in her hands. To stop her, Kenna and Catherine team-up in "No Exit."
Official Synopsis of "Reign" Episode 18, "No Exit": "When Mary's brother James arrives in France and convinces Mary to return to Scotland, Francis is suspicious and uncovers a plot that would destroy Mary, which causes a rift between them. King Henry's downward spiral continues, leaving Penelope in charge, causing Catherine and Kenna to take drastic measures. Meanwhile, Lola becomes wary of Lord Julien's motives behind his marriage proposal."