Dean hasn’t really snapped under the power of the Mark of Cain since the Supernatural mid-season finale, but with the season soon coming to a close it’s easy to assume that he’ll be descending into darkness soon.
In the penultimate episode of the season, titled “The Prisoner”, we know that Dean decides to take matters into his own hands regarding the Stynes. The family, first introduced in episode 10.18, made a reappearance in 10.21 when the Winchester brothers captured one of them and he revealed more about his family and the fact that the Book of the Damned wasn’t burned by Sam. This led to conflict between the brothers once Dean became aware that Sam has been keeping a rather large secret from him. Not only that, but the Styne family was still after the book and they tracked down Charlie and killed her. This is clearly going to set Dean off.
Meanwhile, Sam is going to need to come to terms with the decisions he’s made regarding Dean and the Mark of Cain. Is he willing to see his plan through no matter the cost?
Don’t miss the penultimate episode of Supernatural airing on May 13 at 9:00 p.m. ET/PT on The CW.