Disclaimer: Supernatural and its characters are the property of Eric Kripke. I do not own any of the characters, except for any OCs, in this story.

A/N: This fic was inspired by a picture by the same name on Deviantart, created by smallworld-inc. A link can be found on my profile page. Check it out, it's heartbreakingly beautiful!

"I love you, Dean Winchester."

Castiel couldn't count the number of times he'd said that over the years, whether aloud or only in his heart. But no matter how many times he said it, it never lost any of its power for him. The angel loved Dean, and for all of his faults, he would not have traded the younger man for anything else in the world. He knew that to be an absolute truth, just as he knew that God was his father, that he was sent to Earth to save the Righteous Man from perdition, and that all the millennia in the world had meant nothing, would mean nothing, without his Dean.

The two of them had been together for nearly ten years now, which to Castiel seemed the blink of an eye. In that time, life had changed dramatically for the Winchesters and the angel. They had all retired from hunting soon after Dean and Castiel returned from Purgatory. It was not an easy decision, but after all that had happened to them in their lives, they decided that they had sacrificed enough. It was time to mend the wounds they'd inflicted on one another and to protect what mattered most – their own family. And that meant settling down and finding a normal life while they still could.

Sam had moved out the year after, getting a house on the outskirts of Lebanon and finding a job, alongside Dean, at the local car garage. Despite leaving the bunker alone for Castiel and Dean, Sam had never kept the two of them out of his life, instead welcoming them to share every happy moment right along with him. He was now married to a lovely young woman named Carla, and they had two daughters named Mary-Jo and Jenna, who at five and three had already mastered the puppy-dog look Sam was famous for and knew how to use it to get their Uncle Dean to do whatever they wanted. Castiel, being a master of the puppy eyes himself, seemed to be immune.

The years had flown by in a steady stream, Cas and Dean at the bunker and Sam building his new family a few miles away. Dean had celebrated his forty-second birthday just three weeks ago, and everyone had been there to throw him a surprise party. His little nieces made sure to tell him how wonderful they thought he was in their own special way, which this year meant spraying silly string all over him the moment he turned his back. If he'd made himself an easy target on purpose, well, they would never have to know that. Castiel laughed along with the rest of them, seeing that ever-present spark of youth that had glimmered behind Dean's eyes for as long as he'd known him.

It was something he treasured, because he knew that although his vessel would never age, Dean would not be granted such a privilege. Already the hunter's light-brown hair was becoming peppered with strands of gray, his stubble almost completely slate-colored. Tiny wrinkles had appeared around his eyes and mouth, crinkling when he frowned or glared but especially when he laughed or smiled. Castiel wondered how that could be, how a man who had been through so much tragedy could somehow have more laugh lines than frown lines. If anything, the tiny marks made Dean even more beautiful to Castiel, and he told him so all the time. He wasn't entirely sure that Dean believed him when he said these things, though.

Castiel had never doubted Dean's love for him over the years – not even a little. After they confessed their feelings to each other, the hunter had immediately become faithful only to him, never so much as looking at a woman with more than an average curiosity before turning his full attention back to the angel he'd pledged his love and loyalty to. Castiel trusted him completely. He knew if Dean felt even a fraction of the adoration for Castiel that the angel felt for him, there could be no one else who would ever make them happy but each other.

Still, now Castiel could sometimes feel his uncertainty and insecurity, a questioning of just how deep an angel's love for a mortal being could reach. When they kissed, Dean would sometimes pull back, studying Castiel's eyes as if looking for something inside that even Cas was not aware of. Then, just as quickly, he would clutch his angel even tighter, pulling him close and kissing him again as if nothing had ever happened. Making love was always wonderful too, an experience Cas had never known could be so frightening and exciting and blissful before he met Dean. The hunter could elicit moans of pleasure from the angel with nothing but the most gentle of kisses, the most careful of touches. But even then, Castiel could sometimes feel Dean waver, feel his whole body wondering if this angel who lay so close to him still felt the way he had ten years ago, or even five.

And although it saddened him, Castiel understood. After all, angels were not supposed to be capable of love at all. Why should he be any different? So when, on the day after he turned forty-two, Dean pulled back from yet another kiss with that same insecure stare he had developed lately, Castiel caught his head between his palms and turned him so that their eyes met, azure blue to forest green.

"Dean Winchester," he asked with a gentle smile and a shake of his head. "What is it about me that still scares you after all these years?"

"It's not you, Cas," Dean answered softly. "It's me I'm afraid of."

"What do you mean?"

"I mean, look at me, Cas. I'm starting to get old now. I don't turn heads like I used to. Hell, I haven't since I hit about thirty-five. And I'm not gonna be getting any prettier. Can you honestly say you're still gonna love me when I'm old and gray, even though you'll still look exactly like you do now?"

"What kind of question is that?" Castiel asked, pulling away from Dean and crossing his arms with a scowl. "Of course I'll love you then. Dean, you've seen me in more hideous ways than any person should ever have to see an angel. And yet you still love me, don't you?"

"Of course I do, Cas," he answered earnestly. "God, you know I do."

"Then there's nothing to question. Your body's age doesn't mean anything to me, Dean; it's your soul I'm in love with. And I'll love you until time itself ceases to pass."

Dean gave him a tiny smile and sank back into his embrace.

"I hope you're right about that, Cas."

Castiel had not been lying. His love for Dean never diminished, even as the hunter's body began to slowly fail him. It was little things at first; gray hair turning white, wrinkles deepening, a constant soreness in the joints that had all been so abused for the first three decades of his life. Cas supported him through it all, healing the pain where he could and offering soft hands and a warm embrace where he could not.

Sam and his family were always there for them too, a constant presence that kept Dean younger than Castiel alone could ever have done. Dean loved seeing his nieces, and when they grew up and had kids of their own, he was there for every birthday, every sports game, and he even coached one of his great-nephews' baseball teams for a while, until he threw his back out one too many times doing it. He taught them the easy things, like how to shoot a gun or how to stick up for themselves at school, and also the hard things, like how to be a good person and help others even when no one else around seemed to be doing the same. That one, he credited entirely to Castiel's tutelage.

After Dean unexpectedly had a heart attack at age sixty-five, it was Sam who offered Castiel a shoulder to cry on, letting him vent his worries to the younger Winchester so he could remain strong and supportive for his temporarily bedridden husband. When he did visit Dean, he could see that same look in his eyes as he had twenty years ago, that look that asked Castiel if he still thought the human before him was beautiful. All Castiel could do then was smile and reassure him, but as soon as he was sure Dean was healthy enough, he had held him close and made love to him, more passionately than either of them had done in years. It brought a spark back to the old hunter's eye, and it wasn't half bad for the angel, either.

As Castiel watched his beloved age through the years, he felt great sadness at knowing that soon Dean would have to leave this world behind. Time flew so quickly for an angel, it seemed he scarcely breathed before another fifteen years had gone. Carla had passed away five years ago, leaving Sam and his daughters and grandchildren to grieve her loss. Dean and Castiel had been there for him then, and Dean effortlessly stepped back into the big brother position he'd relinquished for so long, holding Sammy close and stroking his long gray hair while he hiccuped and sobbed into Dean's shoulder.

Not long after that, Dean began to forget the things he had known all his life. Knowledge about hunting, the names of friends and family, even the memories of Hell and the sacrifices he'd made for his family and the world as a whole – all of them began floating away, pouring out like sand through an hourglass. Castiel and Sam watched with sorrow as he forgot even the most basic things; where he'd left his keys, their address, and eventually even how to drive his beloved Impala, which he'd dutifully kept in perfect condition all these years. It wasn't until he fell down the front steps of the bunker and ended up hospitalized that they both realized just how fragile the once mighty hunter had become.

The doctors told them he probably wouldn't wake up at all. Even if he did, his mind was so far gone he likely wouldn't know where he was. Castiel sat beside Sam in Dean's hospital room, hugging the younger Winchester while he stroked his older brother's hand and sobbed. Castiel wasn't afraid for what would happen to Dean if he should die; he knew what Heaven was like now, so he knew there was nothing to fear, and that he would be with Dean immediately after. But Sam would be without his brother for several more years at least, and it made his heart ache for his longtime friend.

When at last Dean opened his eyes, neither of them were sure what to say. But when he smiled and reached for their hands, saying their names almost reverently while the pulse of his weakening heart slowed and slowed, they knew it was finally time. Sam bent down and hugged his brother tight, blinking through his tears as he looked between Cas and Dean.

"I'll see you on the other side, right Dean?" he asked shakily.

Dean grinned at him. "You're damn right you will, bitch."

Sam smiled back. "Jerk."

"So, Cas," Dean rasped as it got harder and harder to breathe. "You still… Love me after all… this time…?"

Castiel held his hand, smiling warmly and kissing Dean's fingers as he felt his soul surging upward in preparation to leave his body. "You still have to ask?"

"Nah. Just thought… I'd check… y'… know?"

"Go, Dean," Castiel said softly, kissing his beloved's forehead when he heard his heart beginning to falter. "I'll be waiting on the other side."

Dean nodded, smiling one last time at Sam, and then closed his eyes, letting his last breath leave him in a slow whoosh. Sam bit his lip, knowing he should be happy but still feeling the tears threatening to fall. Castiel came to his side, hugging him tightly and patting his back.

"Promise me you'll take care of him," Sam whispered. "Just like you always have."

"I promise," Castiel said. "We'll be waiting, Sam."

"Okay."

With a flutter of wings, Castiel was gone, speeding up to his old home as fast as he could; it wasn't every day he got to bring such an important person back with him, after all.

The first thing Dean saw when he opened his eyes was, well, nothing. Everything seemed whitewashed at first, bright but empty. Then he realized it was also very warm, and sort of… fluffy? Well, that was definitely weird. He'd been to Heaven before, and it'd never been white and fluffy. Maybe all the fuzz hadn't cleared up in his brain yet?

Then suddenly the white fluff moved, and Dean found himself lying in the middle of a green field under a beautiful blue sky, dotted with tiny white clouds. The big white thing obstructing his vision had actually been a wing. But that could only mean –

"Cas?" he asked, turning over to face the owner of the fluffy white appendage.

"No, Dean," answered a feminine voice, and his head raised immediately. Even after seventy-six years apart, Dean would always recognize that voice.

"Mom…"

"Welcome home, Dean." She opened her arms and he fell into the hug, letting her wrap her arms around him while he looked around at the familiar faces suddenly surrounding them in the little garden.

"Ellen, Jo, Dad, Bobby…" he choked out, beaming brightly at all of their smiling faces. They were all restored back to their younger selves, and each had been gifted with a pair of wings in varying sizes and colors. Everyone stepped forward and hugged him in turn, and happy tears fell down his face. "Guess the party's almost complete, huh? Everyone but Sammy and… Cas. Wait, where's Cas?" He suddenly felt panicked. Had Castiel chosen not to follow him after all?

"I am right here, Dean," Castiel answered, still clad in his familiar trenchcoat. The only difference now was the pair of enormous black wings stretching out behind him, plainly visible to Dean despite having no walls to serve as their backdrop. "And I'll always be here." He stepped forward, pulling a now youthful Dean into his arms and clutching him tight.

"I love you so much, Cas. And uh, I don't think I'm scared of flying anymore, but… Uh… How do I use these big things?" He gestured to the deep brown wings protruding from his back, and they flapped a little involuntarily.

"Let's worry about that," Cas said, giving him a peck on the lips. "After we've caught up with everyone."

"Oh, yeah. Guess we've got a lot of time to practice now, huh?"

Castiel smiled. "Until time itself ceases to pass."