[Disclaimer: I own nothing but this idea, everything else belongs to the writers of Supernatural.]

Chapter 1

Castiel knew, from millennia of observations, how irrational and erratic the humans could be. He'd witnessed war, betrayal, genocide, heartbreak, and countless other atrocities. Often he wondered why his Father loved them so much more than the angels.

Then he turned his head away from the violence and the mayhem, and he saw the beauty.

He saw the art that they created, life strewn in vibrant colors onto a canvas with a few strokes. Raw emotion coaxed out of their instruments with a few keys plucked in the right order. Incredible passions conveyed with a few symbols arranged a certain way on a page. These humans, finite and seemingly insignificant as they were, could create and feel in a way that was incomprehensible to him and his siblings. Most of them, because they could not comprehend it, chose to dismiss it as meaningless tripe.

Castiel, however, had always been different. The humans, with their wild emotions and their brilliant music and their seemingly endless ingenuity, never failed to fascinate him. For eons he watched them, with an almost childlike wonder. His thoughts danced around them constantly. He didn't understand them, but that just made them even more interesting. They became something of an obsession of his, these strange, confusing creatures that fought and hurt and loved and laughed and lived in a way that seemed all at once dreadful and beautiful to the ancient Seraph.

So when he was finally presented with an opportunity to be involved with the humans, Castiel jumped at the chance. He was eager to see firsthand what earth was like.

He wanted to see a sunset through human eyes, even if it was only a vessel.

He wanted to taste the human delicacies, wine and chocolate.

But most of all, he wanted to see these fascinating creatures up close.

Castiel fought to contain his enthusiasm. They knew of his fascination with the humans, but they did not know the degree of its intensity, and he wanted it to stay that way. If they knew how enamored he had become with the human race, they would never let him do this job. They would keep him locked up here in Heaven, and he would always be trapped, longing to be closer to the humans just beyond his reach. He had to appear detached to achieve his heart's wishes.

They seemed to believe his apparent detachment. They let him go with minimal fuss, anyways.

If he had known what this mission would entail, perhaps he would not have been so eager. Had he been aware of the pain and confusion in store for him, perhaps the angel would have hesitated or even changed his mind.

But he had no inkling—he was an angel, not a prophet. Just an angel, eager to see the objects of his fascination up-close. He departed Heaven forthwith, with no idea what he was getting himself into.

Castiel had not left Heaven in eons. And he had never entered Hell.

He took a deep breath at the gates. The man he was being sent to rescue was vital to the plan—he was to be Michael's vessel, in the apocalypse. He had to be rescued from Hell.

Castiel had been chosen to save him.

They hadn't told him why, and he hadn't asked. That was part of being an angel—you obeyed orders. You didn't question, didn't doubt—you were a soldier.

It grew weary to Castiel sometimes, but he knew it was for the best. It prevented chaos.

He shook himself from his reverie, and plunged into the depths of Hell.

Hell was different than what Castiel expected. Everyone associated Hell with fire and the screams of the damned. Castiel expected flames and heat and agonized cries for help that he would have to ignore.

Instead, he was greeted by cold and dark, silent other than the broken sobs of the trapped souls. It was an inky blackness, more pure and absolute than anything he'd ever witnessed. There was nothing ahead of him but a void, seemingly endless, warning him to turn back, flee, to escape while he still had the chance.

Castiel shivered—the cold did not bother him, but this eerie silent darkness gave him a sense of foreboding. He knew, logically, that he was not in real danger—he was an angel of the Lord, and he could handle a few demons.

The angel took a deep breath and plunged onwards into the smothering darkness.

Time was difficult to gauge accurately in Hell. He fought for what could have been decades, or simply a few moments, Castiel didn't know. He only knew that the tortured soul of Dean Winchester was waiting to be saved.

Save Dean. That's your mission. Nothing else matters.

Ignore the demons clawing at you. Castiel smote them with barely a glance.

Don't look at the other souls. You aren't allowed to save them. That was harder. There were countless souls in Hell, wailing and writhing under the intense torture they were forced to endure. Many cringed away from him, perhaps thinking he was a demon to cause them further pain and misery. Castiel didn't know, and he didn't care because it meant that he could continue past them more easily.

The others, though, the ones grasping at him, begging for salvation…He ached to deliver them—he didn't want to leave anyone here. No matter how badly they had sinned on Earth, he didn't believe they deserved to be left here, forsaken and hopeless.

But he had orders. Save Dean Winchester. Only Dean. So, with a wince and a guilty conscience that he tried to overlook, Castiel carried on further into the depths of the pit.

In the lower levels of Hell, the places reserved for the truly wicked, the ones who committed the greatest sins, Hell became more like what Castiel had been expecting. It was a relief to escape the smothering blackness and the chill, but he wasn't sure this was any better. The reeking smell of burned flesh assaulted him, and he wasn't sure whether it was the damned souls' or his own, because he could feel the Hellfire licking at him, searing his wings and every bit of exposed skin agonizingly.

Castiel wanted to turn back. He was just a seraph, a low-ranking angel. He wasn't cut out for this…but he had to have faith. He had to follow orders. He'd failed his Father before, but he wasn't going to make that mistake again. He would prove that he could be a good, faithful angel. He would not be like his eldest brother, despite what the others said.

Castiel clenched his teeth against the pain and fought his way onward.

After what seemed an endless stretch of immeasurable fragments of time, blurring by in disjointed, whirling images of blood and fire and torment that would be seared into Castiel's mind for the rest of his eternal existence, he found a glimmer of light in the darkness.

The soul he was seeking.

Every soul was different, unique to the human it resided in. Each one looked different, some as bright as a star, others dark as the pits of Hell, and every variation in-between. This soul, though, was Dean Winchester's. Castiel knew it was him the moment he drew near.

It was bright, brighter than any soul he'd seen while watching earth the last few eons. Castiel's breath caught slightly as he stared in wonder—this soul, it was pure, it was good. Tormented, guilty, and slowly breaking, but purely good.

It was fractured, though. After being in Hell for so long, Dean Winchester's poor soul was being worn down, corrupted, the darkness around him attempting to penetrate the purity of the soul, slowly destroying everything good and bright about the human he had been. The darkness swirled around the soul, in a sickening movement almost like a caress, but each touch drew a scream from Dean Winchester and grey smoke would rise, as though he was being slowly burned.

The angel leapt forwards, his Grace piercing through the darkness and banishing it instantly, the vile thing unable to stand anything so pure and righteous as the angel's Grace. The moment the darkness dissipated, Dean Winchester began to sob, a sound so miserable and broken that Castiel worried he might be too late. But no, that couldn't be…Castiel wouldn't let it be so.

He frowned—he couldn't return Dean Winchester in this fractured state. He wouldn't survive long if this broken thing was placed inside the torn-up body the hunter had left behind.

Castiel gathered the pieces of soul to him carefully, almost cradling it, fearful that he might cause further damage if he wasn't careful. He frowned when the soul tried to slip away, and he caught a whispered fragment of its chaotic thoughts.

While there were no words, what it—he—what Dean Winchester felt was obvious to Castiel: he didn't want to be saved, because he didn't believe he deserved it. He thought he deserved to be left here.

Castiel frowned, mystified by this strange reaction. He couldn't possibly want to be left here? Shouldn't he be eager to escape? How bad could his guilt be that he thought he deserved to be left in the lowest levels of Hell to rot? Castiel wouldn't accept it—he didn't believe that he deserved to be left here, and he wasn't going to forsake him to such a miserable existence.

"Stop that," Castiel chided, taking a firmer grip on the soul he cradled, ignoring when it writhed and hissed in pain. "You deserve to be saved, Dean. And I will raise you from this God-forsaken place."

And with that, Castiel fought his way back out of Hell, past all the hellhounds and the demons and the countless monsters trying to keep him back. The fight was a blur in his mind, one monster after another attempting futilely to prevent his escape. The one thing that remained clear to him was that he had to keep Dean safe.

I will save this human, Castiel silently promised, and although he didn't know who he was promising—himself or Dean, or perhaps even his Father—it felt right to do so. I will save Dean Winchester.

When they finally ascended through the gates, Castiel was surprised to discover that he was tired. Fatigue was a rare sensation for angels, not unheard of but not common, either. He must have worn himself out more than he thought. But he had succeeded: He still had a tight grip on Dean Winchester's soul—it had to be returned to his body. But first, he had to be repaired. Dean Winchester, if not broken, was breaking. There were stains and wounds on his soul from that damned place, Castiel knew.

Castiel closed his eyes and ascended further, to a different plane, and he carefully took the fragments of Dean in his hands, his forehead creasing as he concentrated all of his will, his Grace, onto the brightly gleaming soul before him.

The drawn-out scream that followed almost made Castiel falter, but he had to put this soul back together. So he gritted his teeth and continued, the light between his hands growing brighter and brighter, stronger and stronger, until even Castiel could hardly bear it. Just when he thought all hope was lost, that the soul could not be repaired, the light flickered and faded.

In his hands was a complete soul. The soul of Dean Winchester, still hurt and tormented from his recent experiences, but no longer in pieces. He could still see the cracks, the places where it had fallen apart, now held together by Castiel's Grace like a shattered vase being glued back together. It wasn't perfect, far from it, but it was mended enough that it would do.

There was one patch that shone even brighter than the rest—a small piece of the angel's Grace residing in the soul, holding it together. It would always be there, Castiel knew—a scar, a reminder of this whole ordeal. But he had succeeded in his mission: Dean Winchester was saved. That was all that mattered. Castiel smiled, cradling the soul, and descended to a lower plane to reunite the soul with its proper vessel.

They touched down in a desolate field. It looked as though a nuclear blast had gone off. Castiel frowned, wondering if he had landed in the wrong place—but the soul was writhing, fighting to be reunited with its body now that it sensed it was so close.

The seraph smiled, finally releasing his grip on the soul. It flew from his grip and darted over to a patch of dark earth that had a crude cross sticking out of it. It then paused, unsure what to do next. It quivered uncertainly.

Castiel pitied the poor thing—it had been through a lot, small wonder it was disoriented.

"Allow me to help," he suggested, walking over slowly. He placed a hand on the soul, and reached out with his Grace to the body below, forming a conduit for the soul to travel through. It eagerly darted down, into the body.

Castiel shivered when the soul passed through his Grace, shocked as he felt, for the briefest of moments, everything that Dean Winchester was experiencing. The pain, the shock, the guilt…and worst of all was the sadness. This burden was crushing—did humans feel this way every day? How did they bear it?

Then it was all gone. The seraph shuddered at the memory, unsettled and disoriented, but relieved that the staggering sense of emotions was gone. He smiled eagerly, hoping to be there when Dean rose, eager to see his first human up close…

…but precisely then Michael called him home.

Castiel frowned, hesitating for a moment. But he was a soldier, and he never disobeyed a direct order. He sighed in disappointment, and with a flutter of his wings, he was gone.