Define love.

For centuries scholars and poets, psychologists and theologians had struggled to find just the right way to define the feeling – and failed. Nothing came close.

"a strong sense of affection"

"an intense feeling of attraction"

No words could accurately describe it, nor explain the differences between the many forms it could take. People loved each other in so many different ways. There was the love between parent and child, husband and wife, lovers, siblings....It transcended gender, and humanity itself. People loved their possessions, their pets, their hobbies. Patriotism could be described as a type of love, the love of one's country. Certainly there were those who loved God. It was God who had created the concept of love, and who had gifted it upon his next most complicated creation – man. It was, perhaps, only God who fully understood it.

The angel Castiel certainly didn't understand it, even though he was in it.

He was in it entirely against his will, too. That was something else about love. It didn't give a crap what you wanted, or what was best for you; when you were caught up by it, you were its slave. There was nothing else Castiel knew of that would lead a man to sell his soul. Sure, many such men were after fame and fortune, but in some ways that too was a form of love. Most, however, gave themselves up to an eternity of torment for the love of another. Castiel had been a visitor to Hell and seen what happened to souls there. He could not fathom why anyone would willingly do that to themselves.

Lately he'd come to realize that love had a lot to do with it, even though the hows and whys of such a strong emotion still eluded him. It was said angels did not feel emotion. That was wrong. They did, but did so with such an undiluted intensity it simply appeared as if they felt nothing. Angelscould feel, they just couldn't express. Strong emotions remained locked up inside them, building up with little or no means for an outlet, so they avoided the temptation. Such temptation, such emotion, could be crippling. It could lead to a Fall.

Lucifer had Fallen because of his anger and jealousy. Anna had felt longing.

Castiel stood on the brink of Falling - because he was in love.

First and foremost he loved his God. It wasn't his faith in the Creator that had come under fire lately, but his faith in his immediate superiors. For a long time he suspected Zachariah and others were spending more time on their own agendas than following any orders from higher up the angelic food chain. Unfortunately he had not realized this would evolve into a full-fledged civil war pitting angel against angel. Who knew what odd alliances the two factions would form? Angels working with men, with demons? It was unheard of in all of history.

Castiel had never before found himself doubting his orders, nor could he remember having to make choices like he was having to do now. His life, such as it was, had always been easy. Choosing his own path was difficult, but he looked inside himself and realized if he just followed his heart, love would make it a lot easier. His loyalty was to God, not Uriel, not Zachariah. God would understand what Castiel felt he must do, surely.

Still, the final decision was hard, primarily because there was someone else in the equation screwing up Castiel's ability to think clearly. He wasn't sure his decision making process really was based on his love of God - and not someone else.

She was in a holding "cell" awaiting execution. At the moment there were bigger fish to fry than one rogue angel, so she had gotten a slight reprieve. The small room which she occupied was no dungeon, but it had not the opulence of another room nearby that held another, more temporary, captive. Anna's room had unadorned white walls and a single wooden chair, upon which she now sat, fretfully chewing her lip. Said lip curled in a snarl when she saw Castiel. He could not enter the room, but had manifested himself within the glass of a mirror which had appeared upon one wall of her prison.

"What do you want?" she demanded.

Castiel could have argued that he was not the traitor, for he knew she felt that way, but under the circumstances he felt that would be rather hypocritical. "I was misled," he admitted. "Zachariah is one of them. They're going to allow Sam Winchester to kill Lilith."

Anna stared at him in horror. "What? But they said....I heard that Lilith...."

"Is the last seal. Her death will free Lucifer and precipitate war, the Apocalypse. Humanity won't survive." Castiel worried his own lip between his teeth, a gesture, he realized, that was more Jimmy's than his own. "Anna, I'm sorry."

She stood up. "You've got to stop it."

"I can't."

"You have to!"

"I can't, Anna," Castiel repeated.

The emphasis on the pronoun made her realize what he was saying. "Dean," she said softly. "Dean has to stop it."

"They have him, and they won't let him go until they're ready to end it."

Anna's eyes widened. "Until the Earth is scourged."

"Exactly."

She turned away, pacing around to the back of the chair where she paused and looked at him. "And when it's all over, when all of humanity has been destroyed and Lucifer is back in prison, they'll kill Dean too." Her head tilted sideways, ever so slightly. "That's why you're here," she said.

Castiel made his denial in the form of a tangent. "Zachariah is acting in defiance of God's will."

"How do you know?" Anna challenged. "He's been awfully quiet lately, Cas. You don't know how long it's been since God has given anyone any orders."

"I just know," Castiel insisted. "We're talking about God's most beloved creation, Anna. God imprisoned one of the best and brightest of our kind for the love of man. He would not want this!"

"The love of man," the other angel murmured. "And the love of one particular man." She cocked a brow and shot Castiel a wry smile. "You're flushed, Cas."

He was and hated himself for it. "Help me."

"Can you bust me out?"

"No."

Anna snorted. "Well, then you're out of luck in the help department."

"I can't free you, but I can free Dean." Castiel placed a hand on the mirror's glass. "Teach me the spell, the one you used to repel Uriel and I, else Zachariah will stop me before I even begin."

Slightly breathless, Castiel waited for her reply. He'd obviously made his decision, and it surprised both himself and Anna. The jury was still out as to whether he did it for God, Dean or simply himself. Anna would go on to form her own opinion.

"You know what will happen if you do this, Cas," she said. "At best, exile, or imprisonment. Worst case scenario, death."

"Or both," Castiel nodded. "I know."

Anna stepped close to the mirror and put her hand over his. "But I understand. Oddly," she smiled. "He's so very easy to love."

"I'm not...." The heat grew in his cheeks. "I don't. How could I?"

"Chose a different vessel if that bothers you." Anna shrugged. "Our kind are only gendered as the bodies we occupy." She leaned in and whispered, "But in regards to Dean, being female is a definite plus."

Castiel withdrew his hand with a growl and an uncharacteristic show of temper. "Just show me the damn spell."

Chuck wasn't in direct danger from Castiel, but his protecting archangel had been told otherwise – by Zachariah and two others who had joined in the fray. Castiel was out-numbered, out-gunned, and losing the fight by a sizable margin, but then winning was not his ultimate goal. He had to prevent them from following and recapturing Dean before Dean could stop his brother. Castiel was going to keep them away from Dean for as long as he could, even if it killed him. It might have killed him if the tide had not turned when it did.

His foes had him pinned down and all but beaten when they suddenly broke off their attack and left the scene. The reason why wasn't apparent until Chuck turned to look at Castiel with a face as ashen as a corpse.

"We were too late," he breathed. "Lucifer is free."

Castiel dragged himself up off the carpet, staggering weakly to his feet. Now he could sense the disturbance which had sent Zachariah and the others away to attend to other issues. The door to Lucifer's prison had been rolled back. The unique signature of power and presence that belonged to the Morning Star was surging up and outward from inside his tomb. Castiel could also sense the emotional turmoil of those standing directly in his path – terror, guilt, awe, and....desire.

It wasn't sexual desire, far from it. This desire was the lust for power, and it was coming from Sam. He might have realized his monumental error, and regretted it, but he was still corrupted. He'd be no match for Lucifer's coercive abilities, which far outweighed those of the she-demon who had brought him to this place. He'd would swear himself to Lucifer's service, and thus the prophecy spoken by Azazel long ago would come to pass. A demon army would wreak havoc across the planet, with Sam Winchester at its helm.

Dean had no idea of the danger they were in by remaining in the church – or maybe he did. When Castiel arrived he was frantically trying to drag Sam away with him, but Sam was enthralled, staring wide-eyed at the brilliant light shooting up from the floor. He had nothing to lose by staying there. Dean couldn't get him to budge. Castiel saw what the frightened and distracted Dean didn't – the darkness in his brother's eyes that could only mean one thing. As Castiel had predicted, slaying Lilith had pushed Sam too far, irrevocably changing him. He was no longer human.

Sam had been turned as Lucifer had turned Lilith thousands of years earlier at the beginning of time. Only one of her own kind could have destroyed her and that's what Lucifer had instructed Azazel to create. Azazel began it, but Ruby had finished the process, producing a living demon, a being straddling the line between Hell and Earth. Only when Sam's human shell died would he enter the final stage of his metamorphosis. He would become as Lilith had become upon the death of her original shell – a pure and very powerful type of demon. Until then, because he could go where demons could not go, and do things humans could not do, he was perhaps more dangerous than Lucifer himself. After all, it was Lilith who had been the final seal. Such was her power, and she had been one of a kind – until now.

If by some miracle he managed to live through the manifestation of the Fallen angel's true form, Dean would never leave the church alive. There was no question about it. Sam would take his life.

Even as he watched, Castiel saw Sam grasp the knife Dean held in his hand, and heard the whispered command:

"Kill him."

Castiel launched himself across the room. He felt the knife enter his body and heard Sam's gasp as he came to his senses to realize what he'd done. His expression shifted from awe to horror, and his eyes cleared. Freed from his enthrallment he turned and gave Dean a shove toward the door. Castiel brought up the rear as the brothers ran for their lives. The angel knew, however, they wouldn't be fast enough. Grabbing both of them by an arm, Castiel gathered every ounce of strength he had left, and concentrated on a place he knew would be safe, even from Lucifer, who roared with fury when he realized what was happening.

"CAS...TI...EL!"

Lucifer was free, and he was pissed. He let loose an attack that would have annihilated all three of them if Castiel had been only a nanosecond slower. As it was he got clipped by the blast just as he felt time and space skew sideways. Pain exploded throughout his body and his mind, his cry of agony echoed faintly by the soul that still resided inside him. The blow had struck him so hard and penetrated so deeply it had even reached Jimmy.

This, he thought, as his senses grayed, was what dying must feel like.

"Cas?"

He was losing his grip on Jimmy's body, but not complete command of it. His legs wouldn't support him. His head lolled as he slumped against another fleshy being who held him up with difficulty. Wounded, befuddled, it took Castiel a while to figure out this was Dean. The pale, blurry oval floating before his eyes slowly came into focus as Dean's face. He gradually became aware of the dark room surrounding them and the cot upon which he sat. Blinking he saw a shell-shocked Sam sitting on the floor across from him.

Bobby Singer's panic room. They'd made it.

"Cas?" Dean repeated, and snapped his fingers in front of the angel's nose. "Cas!"

"I'm okay," Castiel murmured hoarsely. It was not quite a lie. His power was severely diminished, although if that was a result of the battles he'd been through, the knife still protruding from his gut, or just the very fact he had blatantly disobeyed his superiors, he did not know. "Sam?"

Dean cast a worried glance at his brother, who would not meet his gaze. "Repentant," he said quietly.

"But not saved," Castiel added. "I'm sorry, Dean. I was....too late." He looked away. "I'm sorry."

Almost absently, Dean patted him on the shoulder before going to check on Sam. "Not your fault, Cas. You did what you could."

Castiel sighed, and winced as he pulled the knife free from his body. It shouldn't have hurt, but it did – a lot. The wound was bleeding a lot too, and healing much too slowly. Not good. His reserves were seriously depleted.

"I did what I could," he admitted wearily. "But not soon enough."

Sam got the guest bedroom this time, but they still had to chain him to the bed during the worst of it. Given the telekinetic damage he'd done to everything breakable that they'd mistakenly left in the room, the basement might have been preferable. His withdrawal from the demon blood Ruby had been feeding him for months wasn't pretty no matter where or when it took place. Pain, hallucinations, convulsions – and that was just for starters. Throughout it all, Dean had kept careful vigil, even when a delirious Sam bellowed curses at him. Once a curtain rod had torn itself from the wall and shot toward Dean like a spear. If Bobby had not shouted a warning it would have impaled him right through the heart.

Breaking the addiction wouldn't cure Sam, but it would give him the strength to resist the darkness inside him. It was vital, however, that they continued to keep him as far away from Lucifer as possible. Admitting his brother would never be the same again was a bitter pill for Dean to swallow. Castiel's heart ached in sympathy. Dean would never be the same either.

At the moment both of them slept soundly, Sam in the bed, and Dean in a chair beside it. Castiel stood along the wall beside the door, watching them and wondering just where their road was going to take them next. They had few allies, wanted by angels, demons, and men for their unfortunate involvement in tipping off the Apocalypse. Even in this place, where they had always found safe haven, would soon be too dangerous for them. Since word of Lucifer's freedom got out among other Hunters, Bobby's phone had been ringing off the hook. It wouldn't be long before someone showed up on his doorstep gunning for the Winchesters.

Castiel would do whatever he could to protect them. He wasn't confident, however, that it would be enough. His inherent abilities had returned, but like the brothers, he wasn't what he'd been before. His Fall – and he believed this was now official - had taken a lot out of him.

"When you ask yourself why, what do you answer?"

Turning his head, Castiel was startled to see Anna in the doorway. "How...?"

She smiled faintly. "Friends in high places. There are more like us, Castiel, who have remained true to our Lord despite our indiscretions." The smile faded. "But we are few. This is going to be a difficult battle and the lines that have been drawn are smudged and blurry." She put a hand on his shoulder. "Just keep listening to your heart. It will guide you true."

Before them Dean still slept, his head cradled in arms folded upon the side of the bed. The sleeve of his tee-shirt had been pushed up slightly, revealing the burn-mark that was the only physical scar he had carried with him from Hell. Other scars ran deep beneath the surface, manifesting in the nightmares that still plagued him. Even now his brow was creased and a whimper caught in his throat. Castiel moved away from the door for a moment, just long enough to brush his fingertips across Dean's temple in a warding gesture. Almost immediately the whimper became a sigh, and Dean's sleep deepened, now undisturbed by unpleasant memories. Castiel gently touched his shoulder, and the mark branded there, recalling the daring rescue that seemed to have happened so long ago. They'd been too late to stop the first seal from breaking, but now he wondered if that hadn't been the plan all along.

From the very beginning Castiel had been more concerned about Dean. Had they gotten to him too late? Had he been turned? It had been close, but Dean returned whole and human, much to Castiel's profound relief.

"I need an interpreter," he said quietly, returning to Anna. "Because I sometimes have difficulty understanding what my heart's saying."

"Or you just don't want to know. What are you so afraid of, Cas? Getting rejected?"

Castiel shot her a glare. "There will never occur such a situation that would result in rejection."

"So," Anna said slyly. "If Dean woke up right now and told you he was madly in love with you, wanted you to be with him for the rest of his life, you'd just accept that?"

"I wouldn't have to. That scenario would never be."

"Why not? A pretty female vessel, a little flirting...."

"You disgust me."

"Don't be a prude, Castiel. If sex were entirely about procreating, God wouldn't have made it so much fun."

"And now you blasphemy. It's not about sex, Anna!" Castiel snapped back. "Why do you even bother to torment me with this? You're the one he chose."

It was as close to a confession Castiel would ever make, and it was colored with jealous resentment. They both heard it. He quickly looked away, ashamed.

"You're right," Anna said after a pause. "I'm sorry."

Castiel took a breath and nodded. He pulled himself together and told her the truth. "It wouldn't be me who would be hurt, and you know this. If you didn't, you would have returned to him." Turning around he captured her in his gaze. "Isn't that right?" When she didn't respond, he continued. "Wearing the suit of a human doesn't make us one. It does not, cannot, change what we are inside. We aren't one of them. We don't belong among them. It's....unnatural, and ultimately it's going to destroy them."

Slowly, Anna nodded her head in agreement. "All that though, doesn't stop the feelings, does it?"

"No," Castiel whispered. "It doesn't."

He was relieved that she did not linger, but instead took herself away, perhaps to ruminate on what the conversation had revealed about him, and herself. Castiel himself reflected upon what she'd told him regarding their allies. The situation was grim, there was no doubt about that. He took a walk through the wrecking yard, deep in thought, for over an hour.

When he returned to the house he was surprised to see Sam sitting on the porch steps. He looked rough, Sam, with dark circles beneath his eyes, sunken cheeks and very little color. He was still sick, and weak, but obviously on his way to physical recovery. Emotionally, however, he was a wreck. The feelings Castiel sensed from him were all variations on the theme of bleak self-loathing, but as the angel approached they shifted slightly, taking on a more sympathetic flavor. The sympathy was directed at Castiel, for reasons Sam wasted no time revealing.

"I overheard you and Anna."

Castiel stopped in his tracks. He wasn't sure what to say. Ultimately he chose nothing, which seemed fine with Sam.

"I should have never left them, gone to college," Sam continued. "I should have never tried to be what I'm not, and maybe Jess would still be alive." Slowly, almost painfully, he got to his feet. He caught Castiel's eye. "I'm just trying to say – I understand." He concluded with: "I won't say anything to Dean."

"I'd appreciate it if you wouldn't," Castiel said roughly.

"It's best I don't, for everybody involved." Turning, Sam began making his way back toward the door.

"Sam."

Sam paused and looked back over his shoulder. "Yeah?"

"I...we....I don't know if there is a way to save you, but if there is....."

A wry smile told him Sam had caught his meaning. "Yeah, I know. Thanks." The smile faltered for a moment. Sam turned around and came back to the steps but did not sit down. "You know, Mom always told him angels were watching over him." Hesitantly he added. "You will, won't you, Cas, watch over him? No matter what happens?"

Castiel answered softly after a long pause. "Do you really need to ask me that, Sam?"

"No," Sam admitted. "I guess not." His expression was grim. "But....you will? even if you have to protect him from me?"

The answer this time was immediate. "Yes."

"If you kill me, he'll never forgive you, even if it's to save his life. You know that don't you?"

"I know," Castiel said softly. "So let's not allow it to come to that."

Sam made a soft sound, not quite a laugh. "I'll do my best to be a good boy, promise."

"I'll hold you to that promise."

With that, Sam returned to the house, leaving Castiel alone to reflect once again on the vagaries of love, particularly where Dean Winchester was concerned. It was becoming obvious that Dean put love and sex into two entirely different categories. He chose Anna, not because he fell in love with her, but because he sensed the opportunity to heal some hurts he couldn't share with anyone else. Sex had simply been a by-product of their relationship, a purely physical attraction. All the women he met took care of his physical desires, because emotionally there was absolutely no room for anyone else in his life. Family took priority in Dean's world, and his heart was owned completely and totally by the only family he had left.

Sam, who was so very close to breaking him beyond repair.

And if Dean broke, then who would save them from Lucifer?

Castiel sat down on the porch steps with a sigh, turning his face towards the heavens, and praying for the strength to pick up the pieces if it came down to that. Sometimes he wished Dean weren't such high maintenance, but then, if he weren't, he wouldn't be Dean, and Castiel wouldn't.....

I wouldn't have such a strong sense of affection for him.

"Right," the angel muttered to himself. "You've gone AWOL for the man, Cas. If that's not love I don't know what is. Actually, I don't know what love is and that's the whole problem. Humans don't come with operator manuals. They're complicated, frustrating and...."

"Lucifer must have pegged you good, Cas. You're talking to yourself."

Castiel scowled. "And they interrupt you when you're praying."

The screen door squeaked. Dean came out of the house. "Is anybody listening?"

"I don't know," Castiel sighed. "But I hope so."

And I hope you weren't.

"Yep," Dean said, and sat down on the steps next to him. "That's what it's like."

"What?"

"Being human, having nothing but blind faith to go on. Hard to keep believing in something when nobody answers your prayers." He took a long pull from the beer he held, and handed a second bottle over to Castiel. "Here."

The angel looked at it askance. "What's this for?"

"You need to loosen up."

"In case you haven't noticed, Dean, the Apocalypse has begun."

Dean grinned. "I've noticed, but if it's the end of the world, we've got nothing to lose by getting shit-faced drunk, right?" He paused. "What are we going to do about it tonight, Cas? Huh? Nothing, so let's enjoy the time we've got while we've got it."

"By consuming alcoholic beverages until we vomit?" Castiel asked, but drank anyway. Jimmy's taste buds rebelled, making him grimace. "Sounds like fun."

"You don't know the definition of fun – obviously." Dean leaned into him and whispered. "The goal is not to puke."

Castiel snorted softly and took another drink. "I don't know the definition of a lot of things," he murmured. "But I know this tastes horrid."

"We run on a tight budget."

"So knock over a bank and buy some decent beer."

Dean stared. "Holy crap. Did you just tell me to break the law and make a joke?"

"Did I?" Castiel asked, deadpan. "You must be hearing things."

"It tastes terrible, but you're still drinking it."

"You're a bad influence."

"I guess."

They drank on without conversation for a while before Dean said, softly, "Thanks."

Castiel glanced over at him. "For what?"

"Helping us. You really screwed yourself to do it, Cas, but you did, and I'm grateful. I still think we're on the right side."

"We're not on any side, Dean, we're caught in the middle."

"Riiight." Dean took a long pull from his bottle. "We're totally fucked."

"Not my choice of words, but yes, we're fucked."

"As usual." Raising his bottle, Dean proposed a toast. "Welcome to the Wonderful World of Winchester my celestial friend, where the odds are never in your favor and the beer is always shitty."

The clinked bottles and drank. Dean belched, excused himself, and got up to go get more.

Castiel waited for his return, and actually paused to smile to himself. They were on the brink of destruction, and Castiel's heart and mind were in complete turmoil, but he had to admit that there was no other place on Heaven or Earth where he'd rather be at the moment.

And that, he concluded, was the definition of love, whether it be between lovers, brothers....

Or friends.