The plotline: Bella the artifact-trader/stealer was dragged down to Hell several months before Dean was. Now, she has become a powerful demon with one goal. To kill the Winchester brothers.
When Dean found himself pressed to the wall by the damn psychic powers of the damn demons, he knew struggling against this exceptionally powerful demon was useless.
That didn't exactly stop him however.
Sam was inches away, just as trapped as he was, but he had had the sense to stop flailing madly about because he knew it wouldn't get him out. Instead he was scanning the room for something that might be of help, and was considering asking Castiel if he could turn up to save their butts.
The demon-possessed female stepped forward and grinned, her eyes purely black. "I knew you'd still be here when I came back. You two never seem to die, do you? Not permanently at any rate. No, you get by. At the expense of most of your friends."
Dean refused to answer her, but Sam had decided that their best chance of escape would be to stall her. "What do you mean?"
"When I was dragged down to Hell I had but one pleasure. That was the pleasure of knowing that afterward I could come up here and be powerful enough to try ripping your throats out."
"Have we met?" Asked Sam, not really listening. But at her answer, his attention snapped to her like a rubber band.
"I'm surprised you don't recognize me." She said in mock sadness. "It's me. Bela."
"Bela?" Dean and Sam asked in unison.
"Surprise." She spat and pushed them a little harder into the wall, fueling her abilities with hatred. "Remember now, don't you? Remember how you left, leaving me to those hell hounds? I didn't HAVE to go through that torture. I could have avoided it."
"At the expense of us." Sam pointed out.
"LIKE YOU DON'T DESERVE IT!" She cried. She drew a dagger and teasingly swept it across Dean's throat lightly. "But you know what you do deserve?" She leant in a little closer and breathed in his ear "death."
Bela - or whatever was left of her after hundreds of years of torture in Hell - drew back her hand, ready to paint Dean an entirely new face out of his own blood. But at the last moment, Dean's savior grabbed her hand from behind, twisted it behind her back, forcing her to drop the sharp tool. Once again, it was Castiel to the rescue. Dean and Sam dropped to the ground.
"Demon fodder." Castiel snarled as he shifted to hold her so he could smite her.
"Wait!" Sam exclaimed, jumping to his feet. "Bela, at the time we didn't know enough to keep ME out of Hell, we certainly couldn't help you out there. And just standing around waiting for you to come kill us wasn't exactly an option either."
"But you got out." She spat to Dean, and struggled against Castiel, but he had her pinned fairly well. "I had to stay down there. You were pulled out and you were upset. But I was still there and I had been down there longer than you anyways." She tried to grab at him, but Castiel dragged her back, brought his hands to her face, and burned the demon, Bela, out of the woman's body.
"You know her?" Castiel asked, checking to make sure the woman was alright.
"Yeah. A friend of ours." Dean said sarcastically.
"Funny how most of your friends want to kill you." Castiel commented. Whether that was an attempt at a joke or simply an ignorant comment, Castiel's voice didn't portray.
"Yeah." Dean said, not really listening. Instead he was thinking about what would have happened to him if Castiel hadn't pulled him out. He would have ended up a demon. Just like Bela.