Sam woke up in a sea of pain. He was gasping, drowning in it, screaming for it to stop. No sounds, however, just the feel of somebody's hand on his shoulder, pushing him, shoving him. Sputtering. He dragged in a breath. His lungs didn't work. Expelled it.

"Sam, come on, Sammy, wake up!"

He remembered his eyes burning, remembered his head falling apart. Remembered a pillar of light. He wondered if he would ever see again.

"I am so sorry, Dean."

"For what? How is this your fault? Sammy. . .don't you die on me, Sam, don't you dare!"

He opened one eye. He thought it did. Only blackness. And then. . .fuzziness. . .and then eyelashes, framing worried green. He groaned. It hurt a little less than before.

"Sam! Thank God!"

The other eye opened. Eyelashes framing sapphire blue. Another groan.

"What happened?"

Sam pushed himself up. It hurt much less, now. Just a pounding in his chest, behind his eyes, his lower back. He swallowed, hard, harsh. Coughed twice. Nothing rattled.

"I don't know, you tell me," Dean sat back now, concern still written across his face. Sam sighed, lifted one arm experimentally. It didn't hurt anymore. Rubbed his face.

"I talked to Michael," he said.

"I'm sorry, Sam," even Chuck looked contrite. "I couldn't find any sugar."

Dean looked at the prophet like he was crazy (which, Sam reasoned, he very well might have been.)

"Why?" Dean asked. Sam shook his head.

"I had some questions," He said. Remembered something Cas had said just a few days ago. Turned to look at the former angel (crick in his neck – ow).

"Did you know?" he asked. The angel cocked his head, a befuddled look on his features. "Did you know that being a vessel isn't just about blood. Did you know about love?"

Castiel let out a long, slow breath. Nodded.

"What?" Dean glanced back and forth between the two. "What are you talking about? Sam, did that douche addle your brains, or something? Make some Sam Soup out of your head?"

"The fires," Sam sighed. He leaned forward, put his head in his hands. "They started the fires. So that we couldn't love."

"What kind of bullshit are you spewing?" Dean looked angry now. Cas just looked sad.

"Yes," He said. "I am sorry. Love comes from God, is God. A human possessing great love makes a poor vessel – he is already too full to let in an angel."

"Bull," Dean spat. "I call foul. We know how to love, don't we Sam?"

Sam considered for a moment. He knew that he could feel love, still, could love people since the fire. He knew he was still open to it, wondered how the angels couldn't know that. But Dean. . .when Sam thought about it, he couldn't think of a single person that Dean had loved since that first fire.

Bobby, Sam, Dad. That had been Dean's life. All three people he'd known from before.

There had been Cassie, but look how willing he'd been to leave her.

Ben and his mom.

Anna, though he'd had no problem getting rid of her, either.

So, Sam thought, maybe Dean would make the perfect vessel. The only one he had left was Sam.

"Not lust, Dean," it was Cas who had the courage to say the words. "Not a fling with a woman. Long, heaven-enduring love."

A glimmer of an idea had formed in Sam's head. Granted, his last plan hadn't gone so well, with the nearly being smote by an angel. But this one. . .

The angels didn't really want the Apocalypse. They just wanted to find their Father.

"Cas," he said slowly. "Can angels feel love?"

The former angel looked at him. A long, steady look. Sam met it, blue eyes to hazel. Held it. Sank into the sapphire. He heard Dean's cough, but he said nothing.

"No," Cas said finally. "No. They are completely empty of love. Only God can fill them. That is why we are all . . .they are all. . .desperate to find him. To be full again."

Sam bit a lip. Had one question to ask, one last piece of the puzzle.

"When Anna fell, she was reborn as a human. She had no memory of being an angel. Why are you still. . .you?"

They didn't break eye contact. There was a power in this.

"Anna did not fall," Castiel said finally. "She pulled out her Grace. She landed on earth. She was still an angel. She never knew love."

But Cas had. Sam was sure of it.

"Okay," he said. "I know how to stop the Apocalypse."

"Really, college boy?" Dean raised an eyebrow. "Care to clue us in?"

Sam turned now, decided to try his newfound angel-trick on his brother. Locked eyes. Staredown.

"Do you trust me, Dean?"