Last week on "Supernatural," the show took a break from the Darkness. But this week it is going to be the main and only theme the show will have on it.

Episode 9, titled "O Brother Where Art Thou," will air on broadcast network the CW next Wednesday, Dec. 9 at 9 p.m. EST, according to TV Guide.

The thing about this show is that no matter how big the enemy is in each season, fans still love to watch the "case of the week" episodes. But just like with every season, there is always the return of the season theme.

According to Spoilers Guide, Amara is now fully grown and actress Emily Swallow has taken over her role. There is a strange attraction, or a bond of some sort, between her and Dean Winchester. Suffice it to say that the Mark of Cain may have had some residual effects spilling over them from both characters.

But when she returns, it will be with her own wrath laid down over a town of people. She will also issue a challenge to the people and the Winchesters, so the showdown may be coming sooner than fans may think.

What Dean tries to figure out is why he so intensely under Amara's power. He is strangely attraction to her and the hold she has over him leaves him baffled, but not out. He is determined to figure out a way to defeat her, but he is also conflicted with it.

But the real shock is going to come in the form of Lucifer's return. Or at least it would appear to be that way based off the promo for the episode. Sam and Crowley will go rogue in this episode and hatch a plan that is expected to have disastrous consequences. That plan may very well be Sam answering God's advice and going back up against Lucifer in the cage, or even releasing him.

Watch the preview below for the episode.