So this takes place during 9x04. It basically follows the plot of the episode (with minor details changed and things added obviously) so if some of the dialogue sounds familiar, that's probably because I didn't write it and you're remembering it from the show.

Enjoy!

…

Castiel stood in the centre of the department store taking in the massive selection of menswear and feeling hugely overwhelmed as he did so. There was so much choice, too much choice. His experience of humanity up until now had largely consisted of scrounging for the bare minimum and now here he was, rested and fed and preparing to pick out whatever clothes he wanted, and he suddenly had no idea what to do. He looked over at Dean who was watching him.

"Well?" the hunter asked, "Where do you want to start?"

Cas looked back at the racks upon racks of pants and shirts and sweaters and jackets. He looked back at Dean.

"I have no idea."

Dean laughed and then took pity on the guy.

"Alright," he said, leading them over to a display of jeans, "we'll start with the basics."

After breakfast and a few hours spent lounging around the bunker in Dean's borrowed clothes, Dean had announced that Castiel needed a wardrobe of his own.

"It's not that I don't like seeing you in my clothes," Dean explained with a suggestive smile and wink that did strange things to Castiel's body, "but you really should have some things of your own."

So here they were in some mall with Dean throwing clothes at him, a new credit card courtesy of Crowley sitting in the hunter's wallet. This one had his name on it, his real name; Dean Winchester stamped right into the plastic for the first time in his life.

They got a few pairs of jeans, some t-shirts, long sleeved shirts, sweaters, pajamas, socks, and underwear. Dean dragged him to the footwear department to pick out a pair of sneakers and from there they made their way to formal attire.

"Just in case you end up coming with us on hunts." Dean said by way of explanation, then added with a smirk, "Maybe this time we'll actually get a suit that fits you."

Castiel didn't have the heart to tell Dean that he wouldn't be going on any hunts. Ever. He recalled the last time he tried to join Sam and Dean, his time as a third wheel. It hadn't work out well and now that he was human, he would probably prove to be worse than useless.

But he let Dean pick him out a suit anyway and while Dean was trying to decide between blue and black, Castiel fingered the tan overcoat on the mannequin he stood beside. It was similar to his old one but nicer, more fitted. Also it wasn't covered in blood, which was a plus. He missed his overcoat; missed what it had come to symbolize and the memories he had come to associate it with. He remembered when Dean had pulled it out of the trunk of his car after Castiel regained his memories. The way it had been washed and folded, taken care of, the last vestiges of Castiel Dean had to hold onto. He remembered the way Dean would sometimes straighten it when it had become disheveled because sometimes Castiel forgot about the cloths, they were just and extension of his vessel after all and a new concept to him. He remembered how it had felt like a safety blanket after he had taken on Sam's burden, when his mind was unstable, his thoughts elusive, forever flying away from him. He remembered using it to protect himself, arm himself as though, if he could wrap himself up in the old Castiel's coat, he could become that angel again, but better: more compassionate, more astute, less foolhardy.

"I think we should go with dark blue." Dean said finally and Cas dropped the sleeve like he had been burned and turned away. He wasn't that person anymore, that angel. He was a man now, powerless and useless.

He looked up at Dean who was holding out a suit and shirt with such a look of love in his expressive green eyes. No, not useless, not so long as he was responsible for putting that expression on Dean Winchester's face.

They bought the suit as well as a few shirts and ties and the Impala's trunk was filled as they headed back to the bunker, blasting classic rock and singing along; well, Dean was singing, Castiel was trying to learn the lyrics so that he could join in the next time.

...

Sam and Kevin were sitting at the map table when Dean and Cas got back, lugging their shopping down the stairs.

"Hey, how was the – woah." he exclaimed when he saw the mass amounts of bags each man was carrying. "So you guys bought some stuff than?"

"Yeah, you know, the basics. I also picked up season one Game of Thrones figure we're due for a break after everything that happened, I thought we might order some takeout…"

Sam nodded at Dean's suggestive shrug.

"What have you two geeks been up to?"

"Well," Sam said, sitting up in excitement. "I know you're warded Cas and the bunker is the safest place you could be but I was thinking that it might be helpful if we could track the angels. Make sure they don't get too close. Better safe than sorry right?"

Castiel nodded.

"It would also help to know if they were organizing, grouping onto factions."

Dean looked over.

"Is that likely?"

"They are lost, confused, and angry. Angels were not created to have free will like humans. We were created to follow orders. It's what we do best. I think the last few years have proved that we don't do well when we try to lead. I have faith that if the right angel were to take charge, he could unite heaven peacefully. But unfortunately I am not overly confident that the right angel is the one most likely to take power." His tone was sad as he ruminated on his fallen brothers and sisters and his own past mistakes.

Dean nodded, "Well, we'll just have to keep an eye on those dicks. What'd you guys come up with?"

"Well," Kevin said, sitting up, "This thing lit up like a Christmas tree when the angels fell. Turns out, every dot was where a cluster of angels fell. So we were thinking that maybe there was some way to hotwire it to make it track angels."

Dean looked impressed, "You come up with this?" he asked the young prophet.

Kevin looked over at the younger Winchester.

"Actually, it was Sam's idea."

"Awesome," he said, clapping his brother on the back, "So, how would it work?"

"We have no idea." Sam admitted, "At first, I thought the table was the computer but it's not, it's just a part of it. But we found these cables underneath and we followed them. You're never gonna believe what we found."

…

After trying, and failing, to discover how the computer worked or what was powering it, Dean turned to Kevin.

"You have any idea about this stuff?" he asked the former advanced placement student.

Kevin shook his head.

"I was always more of a chemistry, theoretical physics kind of nerd."

"Yeah," Sam added, "and I don't think the men of letters has IT support anymore."

Dean nodded.

"I think I know someone who could help us." he said, standing.

"Charlie?" Sam asked.

Dean nodded.

"Charlie. Come on, I'll call her." He said, taking out his phone as he and Sam left the room.

Kevin turned to Castiel.

"Who the hell is Charlie?"

The former angel shrugged.

"I have no idea."

…

After Sam left to fetch Charlie, who was luckily still in Topeka, Cas and Dean gathered the masses of bags from their shopping spree and Cas started for the room Dean had designated his the night before.

"Hey, where do you think you're going?" Dean asked.

"My room?" Castiel answered uncertainly.

"Oh, right. It's just, I thought, after last night maybe you wanted to…" he trailed off, face heating.

"Wanted to what?"

Dean sighed impatiently.

"Wanted stay in my room." He mumbled to his shoes.

"Oh." Castiel exclaimed, "Are you sure?"

"Well, if you don't want to that's fine." Dean shrugged, struggling to sound uncaring.

"I would like that." Castiel said, taking a step towards the hunter.

Dean's head shot up and a smile grew where his frown had been.

"Really?"

Castiel nodded.

"Yes."

He slipped past Dean into the room, their room, and smiled, setting the bags he had been carrying on the bed and starting to unpack as Dean cleared space in his dresser.

As Castiel was going through the bags, pulling out clothes and folding them, something caught his eye.

"What's this?" he asked, pulling out the trench coat he had been eyeing.

Dean turned around and his face flushed when he saw what Cas had found.

"Oh that," he said, rubbing his neck self-consciously, "I ah, saw you looking at it, thought you might like it. We can always take it back if you don't I just thought…"

He trailed off.

Cas looked at the coat.

"I do appreciate the gesture Dean it's just…I not that person anymore." He looked up with sad eyes. "I'm not an angel. I can't zap you anywhere, I can't heal your wounds, can't even heal my own." He rubbed at his sore ribs, which were a constant reminder of his now mortal state, "I'm useless."

Dean's face screwed up in anger.

"What? What the hell are you talking about? Hey," he stormed over to the dejected man, grabbing him by the shoulders and spinning him around to face Dean, "You are not useless you hear? So you don't have your mojo anymore so what? I'm human, Sam's human."

Cas looked up with a cold expression.

"But you two have had an entire lifetime to get accustomed to your humanity. I have not. You said so yourself, 'baby in a trench coat' remember?" he said angrily, brandishing the coat that looked so much like his last one.

Dean sighed.

"Yeah I remember and I was an ass to say that because you're not useless. Yeah you may not have your mojo anymore but you've still got all that knowledge floating around in your noggin, that's gotta be worth something and besides you have no idea how much you've helped me just by being here. You are not your grace or your strength or your healing powers. You are you, and that's all you need to be. That's all I want you to be." He sighed, taking the coat from Castiel, "Look, I'm sorry for buying this all right? I'll take it back tomorrow."

"Wait." Cas grabbed Dean's shoulder as he started to turn, taking back the tan trench coat.

"I want to keep it."

"What? Why?"

Cas looked up at Dean.

"As a reminder."

"A reminder of what?"

"Sometimes you forget how important you are to other people, how worthy of love you are and in those times I am there to remind you. This is to remind me that you are here for when I forget."

The words were sappy but, spoken in Castiel's candid manner, cut right through the layers of bullshit that Dean had wrapped around his heart and he couldn't help leaning down and kissing the fallen angel. It wasn't a heated kiss, full of want and desire; it was soft, tender, loving.

He pulled back, staring into Castiel's unbelievably blue eyes.

"Cas I-" I love you. The words caught in his throat. He knew they were true but he just wasn't ready to say them out loud. The only person he'd ever said them out loud to before had been his mom. He cleared his throat to cover up the pause and said instead, "Thanks." It was lame and a cop out but Castiel smiled up at him anyway.

"You're welcome." He looked down at the overcoat still held in his hand, "Thank you for my coat."

Dean smiled and chuckled.

"You're welcome."