The midseason finale of "Supernatural" will air on Tuesday, and the episode is not expected to end on a high note for the eldest Winchester brother, Dean, who is still affected by the Mark of Cain.

A promo of the episode shows Dean talking to Castiel about the Mark, and finally admitting that everything is not under control. The episode is titled, "The Things We Left Behind" and it shows Dean having a vision of himself covered in blood when Castiel asks the Winchester brother if the Mark of Cain was still affecting him. Dean then extracts a promise from Castiel that he would take him out if Dean ever goes over to the dark side.

"But don't let Sam get in the way, because he will try," Dean says, before adding that he does not want to go down that path anymore.

Meanwhile, Castiel too is facing his own share of problems when he attempts to get in touch with the daughter of his vessel Jimmy. Once he gets in touch with Claire, the character essayed by Kathyrn Love Newton, she will convince Castiel to break her out of the group home where she has been living, and once she is out, she runs away from him.

Following this Castiel enlists the help of Sam and Dean to track down Claire.

Crowley too won't have a fun time in the upcoming episode and according to the official synopsis, he will face his biggest challenge yet. Although, it is too soon to say what it could be, there is a possibility that the challenge might somehow be related to his mother, Rowena. The character played by Ruth Connell will return in the mid-season finale, and based on the images from the episode, she is still chained up in the cell.

Official synopsis from the CW reads: "Castiel finds Jimmy's daughter Claire (guest star Kathyrn Love Newton) in a group home and she convinces him to break her out. After she runs away from him, Castiel calls Sam and Dean to help find her before she gets in trouble. Meanwhile, Crowley faces his biggest challenge yet."

"Supernatural" airs on Tuesdays at 9pm on CW.