With the season winding down by this episode, a lot is going to be going on. There's the matter of Metatron (Curtis Armstrong) and his angels and Castiel (Misha Collins) and his angels. There's the fight for the throne in hell, between Crowley (Mark Sheppard) and Abaddon (Alaina Huffman). There's the Mark of Cain on Dean's (Jensen Ackles) arm and how that's affecting him. We've already seen some of that, but it sounds like it's going to get much worse. There's also the brothers' relationship that needs some fixing, and perhaps Sam's (Jared Padalecki) concern for his brother and how the mark is changing him will play into that.
At least three of those things will come into play in "King of the Damned." In "Meta Fiction," Metatron told Castiel he sees himself as the hero and Castiel as the villain and he later told Gadreel (Tahmoh Penikett) that he knows how the story is going to end, though there may be some twists along the way – like the Winchesters capturing the angel who had fooled Dean into thinking he was Ezekiel. But what's going to happen during an upcoming meeting between Castiel and Gadreel?
Meanwhile, we've seen the mark of Cain changing Dean, and it sounds like that could lead to a return to his past with torture in this upcoming episode, since he "eagerly accepts" helping Castiel interrogate one of Metatron's angels. What's going to happen there? Will Sam and Castiel have to intervene and pull Dean back from going too far?
Then there's the matter of Abaddon versus Crowley. She's going to demand he help her kill the Winchesters, and she's going to have a "shocking bargaining chip." What could that surprise be? What does Abaddon have up her sleeve?
Here's the official description of "Supernatural" season 9 episode 21, "King of the Damned," written by Eugenie Ross-Leming and Brad Buckner and directed by PJ Pesce:
"ABADDON BLACKMAILS CROWLEY — Castiel (Misha Collins) captures one of Metatron’s angels (guest star Gordon Woolvet) and asks Sam (Jared Padalecki) and Dean (Jensen Ackles) for help with the interrogation. Dean eagerly accepts, which doesn’t go unnoticed by Sam. Meanwhile, Abaddon (guest star Alaina Huffman) demands Crowley (Mark Sheppard) help her kill Sam (Jared Padalecki) and Dean (Jensen Ackles). When he refuses, she reveals her shocking bargaining chip. Also, Castiel (Misha Collins) sets a meeting with Gadreel (guest star Tahmoh Penikett)."
"Supernatural" season 9 airs Tuesdays at 9 p.m. on the CW. "King of the Damned" airs May 6. What are you hoping to see in this episode as the season nears its end?