After Tuesday night's monstrous episode, the Winchester brothers are preparing to face another epic battle against the dark side in the midseason finale of "Supernatural" season 10 next week. 

In the latest promo trailer made for the episode titled "The Things We Left Behind," Dean (Jensen Ackles) is surrounded by several dead bodies and he is covered with blood. Could this mean that he killed those people and went back to his old, evil ways?  

The CW also released the official synopsis for the upcoming episode, which 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 (Jared Padalecki) and Dean to help find her before she gets in trouble. Meanwhile, Crowley (Mark A. Sheppard) faces his biggest challenge yet." 

Dean is also heard begging Castiel (Mischa Collins) to kill him once he becomes dangerous again. 

"Knife me, spike me, throw me into the freaking sun, and don't let Sam get the way because he will try. I cant go down that road again. I can't be that thing again," the elder Winchester brother tells the angel who brought him back from Hell. 

Will Castiel actually kill Dean in the coming episode? 

Meanwhile, the previous episode of "Supernatural" season 10 featured the return of Sheriff Jody Mills (Kim Rhodes), who was joined by a very excited deputy named Donna (Briana Buckmaster) instead of her daughter Alex (Katherine Ramdeen). When asked earlier why Alex was missing in episode 10, Rhodes shared that there would be phone calls and they would know what's happening through Sam.  The episode showed, however, that Jody and Donna have different personalities despite sharing the same career. 

The "Supernatural" season 10 midseason finale airs on Tuesday, Dec. 9, on The CW.