'Reign' season 4 episode 2 spoilers: Queen Mary discovers a traitor in her inner circle; Adelaide Kane teases Mary's fate

A spy attempts to threaten Mary's (Adelaide Kane) trust within her inner circle on the upcoming episode of The CW's "Reign" season 4.

Titled "A Grain of Deception," this week's episode will see one character test the loyalties of the characters closest to Mary. According to the official synopsis, Queen Mary learns that there is a leech amongst her trusted advisors. She immediately takes action and sets out to uncover the traitor's identity.

Meanwhile, Queen Elizabeth's (Rachel Skarsten) quest for supremacy continues. Determined to get what she wants, the queen enlists Narcisse (Craig Parker) to help her. Catherine (Megan Follows) also tries to regain some of the power she has lost by resorting to extreme measures.

Season 4 picked up with a surprise wedding, a kidnapping, and a funeral. Mary is now forced to navigate new waters with only Greer (Celina Sinden) by her side. After the tragic death of Mary's best friend, Lola (Anna Popplewell), Greer will help the queen deal with the many challenges she will soon face. Since the show follows the story of Mary I of Scotland, fans are now wondering if the finale will also follow the real-life royalty's death.

Kane recently caught up with TV Line, and she teased that the odds of her character exiting the series are "pretty high." She also teased that fans should keep posted on the stars' Instagram accounts, where they have been posting images which she describes as "somewhat ominous."

"We have taken some very generous creative liberties with our storylines," the actress said, "but we have kept the bones fairly accurate. I mean, if we were going to throw the baby out with the bathwater, we would have had Francis live. And then none of this would have happened," she went on to say.

The fourth and final season of "Reign" airs every Friday night at 9 p.m. ET on The CW.