Cass might have been able to unerringly track this otherworldly version of himself, but traveling took time.

While Cass could pinpoint the location of the Angel wearing his nametag, the Angel could be gone long before they arrived with nothing more than a quick flap of his wings which, physical or not, clearly had the ability to teleport. After a few days of long drives that resulted in a sudden interruption and a frantic shuffling of scrabble tiles to indicate a wholly new destination from the previously indicated one, Dean was about done with the whole method. The simple fact of the matter was that this other Castiel still had his wings, and in a blip he could be gone from one coast to the other. Hell, in a blip he could make it to the moon. Distance meant nothing to an Angel with flight capability.

"Lily Sunder was right," Dean sighed, passing a beer bottle to Sam after another long day of wasted time, "So long as he can fly, there's no way to catch an Angel. Not really."

He and Sam leaned against the front of the Impala. Mom was sitting on the hood of her car, a beer of her own in hand. Stars spread out overhead, an unoccupied stretch of rocky lakeshore lay before them, the landscape was clear save for great formations of stone that time, water and wind had made fantastic shapes of, and a smattering of winter-dormant scrub brush. They'd parked in one of those places that weren't really considered places by most folks, where there was little between road and sky besides wind, as well as the occasional song of a coyote, but to weary Hunters were little pockets of isolated peace between where they'd been and where they were going.

Lying on the ground by the Impala's front fender, Cass sighed deeply, gazing at the distant water as though lost in thought. It seemed to Dean that they were excluding him, but Sam had insisted that beer and dogs didn't mix. Sam being the closest thing to a canine expert available, Dean decided to believe his brother, though he suspected that Sam's obsession with healthy eating might be carrying over to what he was willing to feed Cass. Bad enough Sam insisted on sucking all the joy out of life by eating rabbit food, but he wasn't satisfied with killing his own food-related happiness, he had to try and get Dean on board with it too, which was never going to happen, but it sure was fun to have something innocuous like that to argue about when the notion occurred. However, Dean didn't much feel like a fight right now, and anyway Cass didn't look like he was missing anything at the moment. Maybe dogs didn't appreciate a good beer in the evening.

It was a tranquil moment, but Dean felt each beat of his heart as a reminder of the inexorable passage of time. He felt the unevenness beneath his hip, where he'd pinned the end of the leash between himself and Baby, and it felt like it was digging into his soul. Moment by moment, the spell was chipping away at what was left of his best friend. With each passing second, Cass sank deeper into the flesh and fur and psychology of a dog, losing himself in the process. Dean couldn't help but wonder idly: when it was over, what of Cass would even be left? Would he live the span of a normal dog, here and gone in little over a decade? Would he even be able to remember how much he'd done for Sam and Dean? Would he understand what he'd meant to them over the years?

Dean had promised not to abandon Cass. Not this time.

But what would they do with him? They couldn't take him hunting. All the scams would fall apart with the presence of an unruly collie tethered to a supposed FBI agent. And what happened if Dean needed to shoot something and Cass suddenly bolted after one shiny object or another, throwing off his aim? It could get him killed. It could get Cass killed. Hell, it might even get Sam killed. They couldn't just leave Cass at the Bunker for days or weeks at a time either. Who would feed him? Who would make sure he had water once he forgot (would he forget?) how to operate a faucet?

One thing Dean knew, dogs were social creatures. He'd sort of always known that, but having been partially of a dog mentality had brought it into sharp focus for him. Isolation was just about the cruelest thing you could do to a dog. People did it all the time, in small doses, a few hours every day, and didn't think a thing of it. But that didn't make it right. It wasn't in a dog's makeup to be left alone. Mankind bred dogs for centuries to follow at heel, to be protector of body and possessions, companion no matter where life took them, no matter the danger or hardship. Dogs were bred to bark in warning against all intruders or assailants, be they man or beast. To huddle against their master in arctic locales or frigid nights in the desert, providing warmth with their very bodies. To never be beyond the sound of their master's voice, to always come when called. To overthrow instinct and make their personal preferences that of their human masters. To want, above all else, to be allowed to follow, to be with. This was the mold into which Cass had been thrust, and it wouldn't be fair to pretend he wasn't going to have those wants and needs just because he'd been an Angel once… no, let's be honest: just because Dean wouldn't have time to deal with him. Wouldn't want to deal with him.

Dean knew Cass would take it. Both the old Cass, and the dog he was becoming. If Dean willed it, he would wait in the Bunker, alone, forever. Just waiting for the Winchesters to come back to him. Until… one day, they didn't. Or, maybe worse, one day they did, and found him no longer waiting, but instead dead in some corner somewhere, taken by their lack of care and a deep loneliness only dogs could really feel, or just…

Suddenly, Dean found himself blinking back tears as he looked out at the lake. He was glad of the dark, which prevented Mom or Sam from seeing it. It was a dumb thing to cry over. It hadn't even happened yet, might not happen at all. And anyway, what did he want? For Cass to die in battle? Poisoned by some Witch or stabbed by another Angel? But inside, he knew that wasn't what he was struggling not to cry over.

What was really hurting him was that he knew that, one way or another, he'd wind up breaking his promise to Cass. He couldn't help it. He was a Hunter. He couldn't stop being a Hunter for anything. It was in his blood, it was the very fabric that made him. And, no matter what he resolved today or tomorrow, he would be a Hunter always. He could not be otherwise. He simply didn't have it in him, even though he'd tried a time or two to be something else. All that meant he shouldn't try and kid himself. He would abandon Cass again. Because Cass wouldn't be able to keep up. He'd break his heart trying. But in the end, it wouldn't matter. It would all be for nothing.

And the worst part, Dean realized, was that Cass knew. That look in his eyes outside the motel, when Dean had promised not to abandon him, no matter what. That hadn't been a look of belief Cass had favored him with. Cass knew the truth. And he was neither angry nor disappointed by the knowledge, though he had every right to be both. But Cass never was. How many times had Dean said Cass was family, and then turned around and left him out in the cold the moment he became an inconvenience?

It had been impossible to miss the surprised confusion when Sam and Dean had gone after Rowena when she'd put her attack dog spell on Cass. And when that dick Ishim had kicked the crap out of him, Cass had expected Dean to catch him in the blast to defend himself against Ishim, had a look of resignation about it, like he had long accepted his destiny was to wind up as a blood smear on a wall as a result of the battles the Winchesters picked. And hadn't he? Right when he rebelled at Dean's urging all those years ago, Rafael had blown him to bits. And more recently, with Billie. Cosmic consequences. And then Ramiel, he'd expected them to leave him to die in that barn… just as they had so many times before. Cass accepted that as par for the course. It wasn't fair on him. It never had been.

But I'll do it to him again, see if I don't.

The thought was bitter, but Dean knew the unshed tears were more for himself than for Cass. He was a sorry son-of-a-bitch, and he did the same stupid things over and over, year after year, in an endless cycle he couldn't figure out how to break. And Cass, among others, suffered for it. It was no good telling himself he was going to change. There was too much hurt, too much anger, too much broken inside him. He was built on it. He didn't even know who he'd be if he tried to tear all that out.

Dean took a long pull of beer, feeling a flicker of irritation as the line from a country song he'd heard in some bar passed through his mind, 'I'm not cryin' cause I feel so sorry for you, I'm cryin' for me.'

Before the beer could wash out the unwonted self-reflection and unexpected emotional upheaval, Dean's thoughts were interrupted by the sound of a low growl. Tilting his head, he looked down at the collie. Cass had raised his head stiffly. The growl rose up from inside him as he got tensely to his feet, ears far forward, eyes focused on some unseen something seemingly directly in front of him. The glistening fang tips peeked out under the curled lip as the growl worked its way out of his chest and built in his throat. Fur began to rise on the rigid shoulders. Suddenly, the ears flipped back and pinned, and a sound almost like a roar erupted in place of the steady growl.

"Whoa, hey," Sam slid off the Impala, eyeing Cass warily, then looking around.

There was nothing in view to account for the sudden rage of the Angel dog. He was confronting something, but it wasn't physically present. Or maybe, Dean thought darkly, it didn't exist at all.

"Cass?" Dean spoke questioningly, but Cass did not appear to hear him.

One roar became a flurry of them, and the powerful jaws snapped at air, the white teeth clicking together on nothing. The collie head dropped below the bristling shoulders and the stiff tail went down until its end was pointed at the ground, but the sound of menace did not subside.

Then, as though suddenly exhausted, Cass cut himself off mid-roar and abruptly sat down, head low. The fur lay down, the teeth vanished from sight. The ears remained pinned back, giving him a look of defeat. But defeat by who? Or what?

"Cass?"

At the repetition of his name, Cass lifted his head and looked at Dean. There was a hopeless, beaten look in his eyes, and Dean half-wondered if maybe it was the motorcycle chase all over again, a vain, empty-headed pursuit of he knew not what, and which left him afterwards disoriented and confused.

"What was that about?" Sam asked no one in particular, because he knew nobody had any more idea than he did.

Except maybe Cass, and of course Cass couldn't tell them unless they broke out the scrabble board; something Dean felt a sudden and very keen reluctance to do, like maybe he really didn't want to know the answer. He noticed Sam didn't go for the board in the trunk either. For his part in the little exchange, Cass made no attempt at reply, or to encourage them to give him the tools to do so. It seemed he no more wanted to tell them than they wanted to know.

Emptying his beer, Dean decided to call it a night at that. Leaving Sam and Mom with the cars, he led Cass away down to the lake, and then unclipped the leash. In a quiet area like this, downhill and out of sight of the road, it seemed safe enough. And besides, Dean couldn't in good conscience keep Cass leashed all the time. Leashed at all was more than he'd ever wanted to do.

"Go on," Dean said when Cass simply stood and stared at him, "Do whatever it is dogs do before bed."

Cass stared at him a moment longer, and then turned and walked off disappearing in among the formations of rock lining the shore. Dean didn't know how far he'd go, or how long it would be before he came back, and he assured himself he didn't care. Even crippled as he was, Cass had helped them solve not one but two cases that did nothing at all to help himself. The least Dean could do was give him a few minutes of the freedom he'd fought so hard to earn back when they derailed the Apocalypse.

And then again from Rafael. And Naomi, Metatron... and so on and into the night.

Sam had remarked once that free Angels were a new concept for the universe. The Angels had been around since… well… ever, basically. And in all that time, only one of any note had rebelled, and he'd been pure Evil in the oldest sense of the word. By Sam's theory, the universe was taking a little time to adjust to the concept of free-thinking Angels. But often it seemed to Dean as if, rather than adjusting, the universe was set to wipe them out if they didn't go back to their old ways of conformity and obedience. It wasn't fair. It wasn't right. But that's how things seemed to be. Especially on bad days.

Dean didn't count the minutes before Cass reappeared, or he tried not to anyway. But he did notice that Cass returned to him with evident reluctance, slinking out of the scattered brush as though he would have preferred to remain hidden within the shadows of the rocks surrounding them. He carried his head low, and avoided looking at Dean as he approached, as though he had done something of which he was ashamed.

For the sake of safety when they returned to the road, just in case, Dean reached to clip the leash back on the leather collar. Cass ducked his head, and Dean could've sworn he heard a soft, under-the-breath growl. Unbidden, thoughts of Cujo came to mind, though Dean had never actually seen the movie. But one could hardly be in his line of work without hearing the references to it. The good dog sudden gone mad, who turned on his master and ate him. The thoughts weren't rational, and there was no reason to consider that Cass might be going rabid in addition to all the rest of it, but Dean pulled his hand back reflexively anyway. He had borne witness to the short work a dog's teeth could make of human flesh. And those had been just ordinary dogs. A dog with even a hint of Angel power behind it… he didn't want to know.

"Hey," Dean spoke warningly, remembering how Cass had acted just before being unleashed, hoping sternness might tear the Angel dog's thoughts from whatever imaginary monsters were plaguing him, "We agreed this was for you own good, remember? I don't like it any more than you do."

Though Cass seemed not to hear Dean, he didn't duck his head or growl when Dean clipped the leash to the collar's ring. In fact, Cass didn't appear to be paying attention to Dean at all, but a fixed point uphill, towards the road, where Dean had left Sam and Mom. It was only then that Dean realized the growl he may or may not have heard hadn't been meant for him.

Instinct warned him to listen to Cass. Not to belittle or discount what he couldn't see just because he couldn't see it. Suddenly more uneasy about whatever was up there than the Angel dog, Dean slipped a hand to the gun in his waistband, even as the other held to the leash.

"What is it?" Dean inquired, "What's up there?"

The only response was a cavernous growl.