'Salem': Mary Issues a Final Warning (Exclusive Video)

Mary Sibley has had enough on WGN America's Salem.

After discovering that the coven is conspiring behind her back, Mary (Janet Montgomery) -- in a scene from Sunday's episode exclusive to The Hollywood Reporter -- takes matters into her own hands.

In a tense confrontation with Magistrate Hale (Xander Berkeley), Mary lays down the law. After all, it's her who got the witches on the path to achieving the Grand Rite, a point she has no problem making.

"Much worse for you, you underestimated me," Mary says.

"Do you have any idea what you've done?" Hale pleads.

"Question isn't whether I understand what I've done, but whether you understand what you must now do," Mary says in a final warning.

Salem airs Sundays at 10 p.m. on WGN America.

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