Episode 16 of "Reign" season 3 showed the Queen of Scotland arriving at her country and finding it different from the country she hoped it was. The country was violent and divided - doubtlessly needing a ruler to unify it. Mary hides her identity as she explores this treacherous land. She also seeks to meet Fancis's killer, Munro.

CW's synopsis for episode 17 says, "Mary is presumed dead, so Elizabeth seeks her crown with assistance from Lola. Meanwhile, Mary's half-brother tries to safeguard her throne from John Knox; and Mary and Bash wind up in the clutches of the intimidating clan leader who killed Francis."

As part of Mary's plan to conceal who she is, she and Bash pretend to be siblings named Pauline and Pierre. A part of their scheme is to pretend that Pierre wants to ransom Pauline whose rich fiancé will rescue her from Munro in exchange for good money. This convinces Duncan to arrange them a meeting with Munro.

Upon meeting Munro, Mary flirts with him with the plan of luring him to his room and proceed to killing him there. However, it soon becomes apparent the Munro knows who Mary is. Mary gets her revenge by killing Munro using the sword Francis gave her. Mary arrives just in time to retrieve her throne from her half-brother James, who was being brainwashed to dissolve the monarchy.

Meanwhile, in England, Narcisse informs his wife, Lola, that Mary is alive upon their reunion. He then declares his love for her and invites her to leave England with him. Lola informs Elizabeth of this in order to stop the invasion to Scotland but the queen does not want to back off. Before she leaves England, Lola receives a note from Mary giving her the mission to kill Elizabeth.

In Frances, Catherin is still in search of her son. She uses the army to attack the red knights. Little does she know that her son has already escaped through Thierry's help.

"Reign" airs Mondays at 8 p.m. ET on the CW.