Since making the welcome discovery that Dean's lust affair with an angel of the Lord was reciprocated, Dean had been trying and failing to get said angel to himself. Either Anna or Balthazar were at dinner every night, and just when Dean thought it couldn't possibly get worse - it did.

They got twice the dinner company when both Anna and Balthazar showed up on their doorstep. It wasn't a quiet dinner - couldn't be with Balthazar trying to steal Cas's attention at every turn, and Anna trying to keep him distracted while directing pointed looks at Dean - and yet, it felt quiet and tense to Dean with Cas shutting him out still and Anna ignoring his attempts at conversation. It was a relief when it was over, even as Dean's mind raced for a way to make Cas - who'd been rushing right out after dinner every night- stay.

"You could try just asking," Anna whispered gently while Balthazar hoarded Cas's attention.

"What?" Dean asked, startled. He hadn't know she could read his mind. "How did you…?"

Anna rolled her eyes. "I don't have to violate your privacy to know there's something on your mind. I'm betting it has something to do with Castiel. You've been shooting him these adorable longing gazes all night. Whatever it is you're thinking or wondering - just ask him."

"I'll keep that in mind," Dean promised wryly.

"Cassie, love, I have another engagement, but need to speak to you first," Balthazar said as he pushed away from the table. "Alone," he added.

Dean growled, but Cas put a hand on his knee before he could protest. "There is no need," Cas said, "Dean can hear whatever you need to say, especially if it involves his brother."

Balthazar glanced briefly at Anna. She was a good friend, but they hadn't filled her in on the whole Sam situation.

"I'll just take these to the kitchen, shall I?" she asked, standing and gathering the dinner dishes. Dean and Cas sent her identical looks of gratitude.

Once she'd gone Balthazar said, "I've had word from Gabriel."

"You spoke to him?" Dean exploded out of his chair and got in Balthazar's face, angry that he'd waited the entire farce of a meal to tell them.

"No," Balthazar said, "He sent me a message that he'd be seeing me soon. He also..." Balthazar pulled an envelope out of the air with a snap. "...sent this."

He handed the envelope to Cas. Dean quickly went to Cas's side as Cas opened the letter and read it through quickly. His emotions did something interesting and hard to follow across the bond and then he looked back up.

"Anael, Balthazar, I would like to be alone with Dean now," he said. Dean hadn't even noticed Anna returning, and dread bore down on him like a physical weight at the seriousness in Cas's tone. He grabbed the letter from Cas's hands, and Cas let him, but the letter was written in Enochian and the only thing Dean could make out was Castiel's name.

"Of course, Castiel," Anna said, grabbing Balthazar's arm and pulling him close to her. "We will leave you at once." Balthazar started to protest, but Anna gave him a look that could freeze fire and they were gone.

"Cas..." Dean said, fear stealing his voice before he could ask.

Cas immediately set his hand over the mark on Dean's arm, sending comfort and strength. "Sam is fine," he said. "The news is worrisome, but not... But not that."

Dean felt like he could breath again and he moved closer into Cas's heat. "Promise?"

"I would not lie to you," Cas assured him.

"Okay," Dean said, almost lightheaded with relief. "Okay. Then what's up?"

"Gabriel has revealed to me why Heaven was anxious to acquire and keep Sam. He is one of Azael's children," Cas told him gravely.

Dean had no idea what the hell one of Azael's children meant, but he had the feeling it wasn't good. "And that's bad," he said.

"Azael is one of the Fallen," Cas said, pretty much confirming Dean's conclusion. "His mission is to create special children to lead his army and free Lilith by feeding demon blood to infants."

"What?" Dean stepped away from Cas, away from his words. Cas let him go.

"The blood gives the children special powers."

Cas said more after had more to say after that, but Dean didn't hear a word of it. He was thinking about Sam's headaches and dreams and all the stuff he seemed to just know before it happened. He interrupted Cas. "Sam's a demon? He could…" Dean couldn't finish. It couldn't be true, not his little Sammy. His brother had the biggest heart, and he always looked for the good in others. He couldn't be… It just couldn't be true. Somebody had made a mistake.

Cas pulled Dean closer again, putting his hands on Dean's shoulders and forcing him to met Cas's kind eyes. "No. He is still your brother. The one you've raised and taught and loved his whole life. That does not change."

Dean closed his eyes and let Cas's words and feelings calm him down. "Right," he said out loud. "Right."

"He's not a demon," Cas continued. "He is just slightly more than human. Only further ingestion of demon blood would corrupt him fully. However, in Heaven's eyes, the threat is still there."

Dean opened his eyes again. "What can we do?"

Cas released him and looked away. "There are a few ways to remove Sam as a threat. Kill him…"

"Not an option," Dean said harshly.

Cas smiled and met his eyes again briefly. "Obviously. Keeping him under the control of an archangel - in this case, Gabriel - is another alternative. The partial bond that we - and doubtless our brothers - share would keep tabs on Sam and make it difficult for a demon to approach him without alerting Gabriel."

"Difficult, but not impossible," Dean guessed. "Not that I'm not grateful that Heaven choose that option, but is there another?" Dean asked.

"Only one other of which I'm aware," Cas said slowly, "but I am uncertain you will like that option any better."

"Hit me," Dean said, unconsciously spreading his legs, bracing as if for a physical blow.

"A full mating bond with an angel would cleanse the taint from Sam, removing his powers and all that Azael might find desirable," Cas said.

"Mating bond?" Dean asked, heart sinking.

"The complete merging of an angel's grace with, in this case, a human soul. The act would purify the soul, but also permanently bond Sam to the angel."

An idea. A horrible, terrible idea was forming in Dean's head. "It have to be an archangel?" Dean asked hoarsely, feeling nauseous with his choice.

Cas stared at him, eyes narrowing, no doubt troubled by the whirlwind of negative emotions Dean couldn't keep a lid on. "No. Any angel's grace would work."

Dean swallowed rapidly against the bile rising in his throat and forced himself to make another sacrifice in the name of his brother. "Do it. Mate with Sam."

Cas took a step back, eyes widening, and then he advanced on Dean again. A whirl of hurt, rejection, and denial from Cas joined the riot of emotion Dean was sending dancing across the bond until Dean was no longer sure who was feeling what. "What?"

Dean had to close his eyes. "You heard me," he said, unable to repeat the command. "When Balthazar sets up the meet with Sam and Gabriel, you should ma… cleanse Sammy."

Cas gave a noise like a sob, but Dean didn't - couldn't - open his eyes. "I cannot," Cas said.

Dean smiled despite himself. He didn't much want Cas mating with anyone - anyone else - but he loved Sam more than himself, and he trusted Cas with his life; and, more importantly, with his brother. "You have to. You just said it's the only way he can be safe and free."

"No," Cas growled, the sound going right to Dean's groin despite the circumstances. "No, I cannot Dean. It's impossible. We cannot mate without love. Our grace would reject the bond, causing injury to both parties."

Dean didn't like the sound of that. Preventing harm to Sam - and to Castiel - was the whole point. He opened his eyes and forced a shaky smile. "So, we'll give it some time. Sam's smart. Friendly, sympathetic, and a believer to boot. You'll adore him. And he's not hideously ugly." Dean put on his well-worn charming smile, pretending he didn't care as he added, "He's not as awesome as me, of course, but you've got a lot in common. And I'm sure…"

Dean lost his excuses as Cas grabbed his arms hard enough to bruise, forcing Dean to meet his angry eyes. "No, Dean. I will never be capable of mating with Samuel. I am in love with another."

For Dean it was like the whole world stopped for a moment. He nearly forgot to breath. The panic and anger in Cas was fading to something painfully tender, and Cas raised on hand to cup Dean's cheek. Dean leaned into the touch, and asked, "You do?"

Cas nodded. "I have been most confused by this annoying fluttering in my chest, the inexplicable tingling in my limbs, the thoughts of you - both carnal and mundane - that I am unable to banish. It took some quiet meditation, and some embarrassing conversations with Anael, but I have finally identified the feeling." He smiled then and it was like a fire was lit somewhere inside of Dean. "I love you."

Dean sighed deeply, relief and joy spreading through him. "You never said…" he started.

"You have little choice in your current companionship," Cas said, watching his thumb where it was slowly stroking over Dean's lower lip, "I did not want you to feel pressure to belong to me in the ways I have been imagining."

Through the bond, Dean felt that elusive emotion that usually only Anna invoked, and this time he identified it readily. Possession. Dean was surprised at how much he liked it. The feeling in Cas was immediately followed through the bond by shame. Dean liked that even more - that Cas would be ashamed of wanting to own him when he thought Dean hadn't had a choice in offering himself up.

Although Dean thought - knew - he would offer himself freely. In fact, "I do have another choice. You've tried to free me lots of times. I choose this," Dean said, pushing his own desires - both carnal and mundane - through the bond, "Besides," he said with a wicked twist of his lips, "if I wanted another choice, Anna seemed willing."

That had exactly the desired effect when Cas growled like the inhuman thing he was and slammed Dean back against the wall, crowding into his face at once, trapping Dean with his weight. "She can't have you."

"No?" Dean teased with a grin, "Don't I get a say in that?"

Cas growled again, but then - with a different display of strength - pulled back slightly, not totally releasing Dean. "Yes, of course you do."

Dean leaned forward and kissed him softly, just a teasing press of lips and a stroke of his tongue across the seam of Cas's lips before he pulled away. "You're right, she can't have me."

"Mine," Cas whispered, all his wild passion suddenly converted to quiet intimacy. It should have made Dean uncomfortable, having so much devotion and wonder aimed at himself. But all he felt was loved and safe and home. Dean very much wanted the opportunity to get used to it.

He hooked an arm around Cas and switched their positions. He knew he could only move Cas because Cas allowed it, but it still made him feel powerful and primitive. "And Balthazar can't have you," he reminded Cas firmly.

Cas looked genuinely surprised at the idea, which made Dean unreasonably happy, and then smiled at him, almost too raw and tender for Dean's comfort. "Of course not. That would be impossible since I belong to you."

There was really nothing Dean could say to that, so he didn't try. He pressed a kiss, slow and tender to Cas's eager mouth and tried to say what his testosterone filled upbringing wouldn't allow yet.

Cas fitted his hand over the mark on his arm, and Dean knew he felt it anyway. All the words of want and need, longing and fulfillment, and love that he wanted time to learn to vocalize.

"Dean," he said, awe in his voice, pushing everything Dean was sending him back along with more back at Dean.

"Cas," Dean answered, kissing him breathless, "bed. Now." Dean was dimly aware of the pull and flutter as they switched locations and then they were in his room, on his bed, Dean straddling Cas. He pulled back to remove his shirt and then leaned back down to get Cas out of his. A process made nearly impossible by Cas's inability to keep his hands off of Dean's chest. Somehow Dean managed to get Cas hopelessly tangled in his shirt. Dean laughed. "Cas, man, help me out here."

The shirt disappeared as if it'd never been, followed in short order by his pants. "Whoa," Dean said, "slow it down, this part can be fun." Dean's pants disappeared as well.

Cas had the grace to look abashed, making Dean laugh again. "So it's gonna be like that, huh?" Dean gripped Cas through the soft cotton of his boxers.

Cas gasped and bucked into his grip. "Dean." He sounded lost, desperate and wanton. Dean wanted to hear his name fall from Cas's lips like that again and again.

"Shh, I got you." He soothed, unable to stop smiling.

Cas apparently not liking the smugness in Dean's voice, narrowed his eyes and copied Dean's move, gripping Dean's cock through the thin layer of his underwear. Then, presumably just because he could, Dean's underwear were gone and there was nothing separating Cas's warm hand from Dean's eager cock.

"Cas," Dean moaned, arms trembling with the effort of holding himself over Cas.

"Shh," Cas said, "I've got you now."

Dean kissed away the smirk Cas had stole from him and lowered himself fully onto Cas, and the angel hastily moved his hand before it could become trapped between them. "So," he said with forced casualness as Cas got rid of the last remaining layer of clothing between them. "Want to tell me about the ways you've been imagining me belonging to you?"

Later, Dean boneless, eyes closed, and more than halfway to sleep he heard Cas whisper to him. "We'll find another way to free your brother. I swear it."

Dean hummed his approval. He believed Cas without a doubt. Maybe that was the orgasm talking or the bond, but he did. "I know, Cas," he assured him lazily. Then, with no input from his pleasure addled brain, Dean asked, "Are we mated now?"

Dean felt Cas tense briefly and he ran a soothing hand down his back even as he opened his eyes to see what was wrong. Cas relaxed almost at once. "There is more to it than the physical bonding," he said.

Dean yawned and pulled Cas closer. "Yeah, like what?" Dean was distantly aware that he was practically asking Cas to marry him, and quickly at that, but the feelings of love and home that Cas was sending him were so perfectly matched to his own that Dean couldn't feel anything but right about it.

Cas pressed a kiss to his chest, sending a jolt of happiness through them both. "Witnesses, words, and intent. And your mark on me."

Dean like the thought of that - his angel claimed and marked for all of Heaven to see. He wanted to ask more about that, but sleep was dragging him down fast. "Tomorrow," he mumbled sleepily, meaning both his questions and the mating.

Pleasure zinged down the bond. "Tomorrow," Cas agreed. "Sleep now."

Dean swore he'd only been asleep for moments when movement woke him. It was Cas, climbing back into the bed. "Cas?" he asked, trying to blink his eyes awake. "Wassup?"

"Nothing, Dean," Cas answered in a whisper to match Dean's, "go back to sleep."

"Everything okay?" he asked, struggling to sit up.

"It will be." Cas gently pushed him back down with a hand to the center of his chest. Dean got a flash of something unsettled from Cas, but it was overwhelmed almost immediately by something that reminded Dean of his mother's tomato rice soup as Cas kissed him gently. He thought he heard Cas whisper and the press of fingers to his forehead as he drifted off, but he was too far gone to be sure. Dean fell asleep with Cas on his chest and peace in his heart.

He woke up in an unfamiliar hotel room with his father.