Sam swung his machete hard and fast. It hit muscle and then bone, and caught, unable to slice cleanly through the neck of the vampire. Sam tugged it out and hacked at the neck again, but the blade was blunted from overuse, and still didn't take the vamp's head off. He could hear Dean making smart remarks as he fought through his own swarm of vampires, trying to get to Sam. Sam brought the knife down a third time, and this time the head came off, rolling away as the body dropped, bloody and lifeless to the floor, only for its place to be filled by another vamp.

This was it. They were going down. Across the room, Dean was shouting something, but Sam couldn't make out the words over the noise of his blade hitting flesh and the rush of blood in his ears. He was backed against the wall, just him against three vampires.

Then suddenly he wasn't. There was a flash of long dark hair, a swirl of tan trench coat, a burst of white light, and then he was dropped unceremoniously on the floor of the motel room.

Beside him, Dean was staring up at the woman who had saved them.

She was staring right back at him.

Sam sat up, wiping blood splatter from his brow. "Thanks for saving us. Uh, who are you?" he asked.

"Hello Sam," the woman said, affording him a brief glance before returning her gaze to Dean. "You two need to be more careful. I have greater concerns than this." But she placed a hand on Dean's face and the cut on his forehead closed.

"Cas?" Sam asked.

Dean stood up, wiping blood from his face with his shirt, and helped Sam to his feet. "You okay, Sammy?"

"He's fine," Cas said shortly.

"I hate to ask the obvious question, Cas, but why are you a girl?" Dean asked.

Cas darted his eyes away from him for a second. "There is a limit to the number of times a vessel can be exploded without permanent damage."

Dean's face took on the expression Sam had seen when Chuck had pulled a tooth out of his hair, but he covered it quickly with anger. "So you tricked this poor chick into letting you use her body?"

"The alternative was burning your eyes out rescuing you after your ill-advised mission to take on the nest of vampires without back-up inevitably went awry." Cas spat back.

"Oh, we're going to talk about going into dangerous situations without back up, are we, Mr Exploding Man?" Dean glared at Cas, taking a step closer.

"You guys don't really need me here for this, do you?" Sam asked. Neither of them showed any sign of hearing him. "Okay, well, I'll be in the shower."

Sam took his time washing the congealing vamp blood out of his hair. If you didn't get it all out, it could get pretty gross. The water ran pink down the drain. He could hear Dean arguing with the new female voice of Cas, and sang to himself to drown it out.

He let the water run cold before he got out. If Dean wanted to stand around picking fights with the angel for saving them that was fine with Sam but he could wash his ungrateful ass in cold water.

Dean was sitting alone at the table, glaring angrily at the empty spot where Cas had been standing.

"Shower's free," Sam said. "You okay? Where's Cas?"

"Back upstairs," Dean told him. "Dammit, why didn't he ask us for help?"

"Dude, he's an angel. I'm pretty sure we couldn't help him anyway."

Dean shrugged, looking unsatisfied, and got up to have a shower. "Kind of weird that he's a chick now, huh?"

Half an hour later, Dean was still in the bathroom. Sam did not want to know what he was doing in there, but chose to believe he was sulking about Cas.

There was a sudden shout of surprise followed by "Shit, Cas. Don't do that!"

The unfamiliar female voice made a short, quiet reply, and then Dean slammed out of the bathroom, saying angrily: "Well, first of all, I didn't recognise you, and second of all, I was naked, Cas! You don't just appear out of nowhere when someone's getting dressed!"

"I apologise," Cas said stiffly, a line appearing between the neat, arched eyebrows of his new vessel as he frowned at Dean. "I was not aware it would be a problem. I see no reason for you to be embarrassed about your nakedness. The human form is aesthetically pleasing."

Dean turned pink and made a weird choking noise. "What do you want, Cas?"

"I came to check on you, since you are clearly incapable of staying out of trouble for more than a few minutes at a time."

"Fine, whatever," Dean said. "Just stop spying on me in the bathroom. It's weird." He flicked the coffee pot on.

Cas watched him closely before sitting upright on the end of Dean's bed and turning on the TV. Dean came and sat next to him, flicking through channels in a vain attempt to find one that wasn't playing advertising.

"So, is it weird being a chick?" Dean asked.

Sam, as was so often the case when Cas was in the room, felt somewhat superfluous.

"It is much the same," Cas said, "Although I find the hair impairs my visibility. I understand now why you keep encouraging Sam to cut his hair."

"You could tie it up," Dean suggested. "I'm sure Sammy's got a nice hair ribbon you can use."

Sam spluttered indignantly, but didn't say anything, because then Dean might remember that Sam was in the room, and notice that he was playing with his totally platonic, newly female best friend's hair.

"I think it would be more practical simply to cut it off," Cas said.

"I think you should keep it," Dean said, "It'll, um, help you blend in. Chicks have long hair."

Sam grinned, seeing his brother go red as he tried to find a reason for Cas to keep the hair without saying he thought it was pretty.

To be fair to Dean, Cas's new vessel was extremely good looking. It made sense. She was related to Jimmy Novak somehow, and Jimmy had been a good looking guy. Sam refrained from asking who the girl was, because Dean and Cas seemed to have got over their earlier fight and were sitting close together, watching TV. Bringing it up again would just cause tension, and Cas would vanish, and Sam would have to put up with Dean being extra grouchy for the next week, like he always did when Cas disappeared. Anyway, Dean and Cas were kind of cute when they were getting along.

This whole Cas turning into a girl thing wasn't nearly as weird as Sam had thought it would be.

"Why did you keep the coat?" Dean asked suddenly.

"I like my coat," said Cas.

"It is kind of badass," Dean said.

"Yes," Cas agreed.

The Sam saw it. Dean clapped Cas on the back and left his hand there. What the hell? Dean and Cas didn't touch each other. Stared deeply into each other's eyes, stood inappropriately close, and had long non-verbal conversations that Sam didn't understand, yes, but lingering touches? That was something Sam hadn't seen before.

"Dude," he said to Dean later, when Cas had gone back to heaven and Dean was sulking on his bed like a girl whose boyfriend had rejected her to hang out with his boys. "Cas is a girl now."

"Yeah, it's weird, huh?"

"It's not that weird," Sam said, because, yeah it was a little strange seeing a random chick standing a six inches away from Dean, but really it was still Cas. It wasn't like he'd turned into someone else.

"Yeah it is," Dean insisted, "He's got long hair. And boobs and stuff."

"That's good, though, right? You like boobs."

"What are you saying?" Dean narrowed his eyes at Sam.

"Nothing," said Sam, and turned on his laptop.

"If it's nothing, why do you keep bringing it up?" Dean asked.

Sam sighed. Seriously? Cas was a girl now, and Dean still wasn't getting it? "Whatever. Just don't get distracted by his boobs in the middle of a case."

"Seriously, Sam. You're being really weird about this."

Cas dropped in again two days later, while Sam was on the phone to Bobby, trying to organise extra hunters to help them out with the vamps. They'd underestimated the number they had to deal with last time, and now there were a dozen angry vampires in the old barn on the edge of town that they had to deal with. Too many for two people.

"Yah!" Dean jumped. "Oh, right, it's you."

"Are you alright, Dean? Your startle response seems to have become more pronounced recently." Cas stepped even closer to Dean and examined him.

"You look different, Cas. I'm not used to some random chick popping up behind me. You might think turning into a chick is no big deal, but we humans are used to people looking pretty much the same every time we see them."

Cas nodded, a strange look on his delicate features. "You don't like my new appearance."

Dean spluttered. "No. It's, um, nice. Very... pretty..." His face was turning red. Sam was reminded forcibly of himself telling Jess he liked her dress on their first date.

"Hey, Cas, since you're here, can you help us with these vamps?" Sam broke through the awkward silence. Man, this was even worse than watching Dean fix Cas's tie for him before interrogations.

"I will deal with it," Cas said matter-of-factly, and disappeared for a second. "The vampires are dead," he said, reappearing even closer to Dean, his hair in disarray, his coat covered in blood splatter.

"Dude, you were gone like two seconds," Dean said, sounding remarkably like a small boy talking to a football player or Santa.

Sam had always suspected Dean thought it was kind of hot when Cas did stuff like that, but now he was sure of it.

"Hey, why don't we all go to the movies tonight," He suggested. "We haven't done something like that for ages. Cas has never been to a movie, right?"

"Well, actually," Cas started.

Sam cut him off. "We can go out for dinner first, get dressed nice all that. It'll be great."

Dean looked at him suspiciously. "What's brought this on?"

"Oh come on. We haven't done anything fun for ages," Sam said. "We just sit around in motel rooms and watch TV. We saved the world three months ago. We should be celebrating."

Dean shrugged. "Whatever."

Sam made Dean take a shower and dress in his fed shirt and jeans, because you had to dress nice to celebrate saving the world, and while Dean was in the shower he pulled Cas aside.

"Take off the coat."

Cas obediently took off the coat. His new vessel had been wearing jeans and a blue t-shirt when she'd accepted him, so that was what Cas was wearing now. It wasn't particularly dressy, but it would do. Sam was pretty sure that if he found her a dress Dean would freak out and run away anyway, so it was probably better this way. Plus, he couldn't really imagine Cas in a dress. It just seemed weird.

"You're gonna have to clean the blood off this before you go out," Sam told him, and in a blink, the bloodstain was gone from the front of the shirt. He handed her a comb and went to get ready.

They arrived at the little Italian restaurant Sam had booked half an hour later. Sam let the waiter lead them to a table and sat on one side, ensuring Dean and Cas were facing each other.

"Why do you keep looking at my chest, Dean?" Cas asked.

Dean picked up a drinks menu and hid behind it. "I – er, sorry. You're a chick, I can't help it."

"I don't mind, I was merely curious," Cas said.

Sam stood up. "I'm gonna go see where the waitress is," he lied.

He made his way over to the host's station. He glanced back at the table, where Dean and Cas were talking to each other, intensely but with little smiles on their faces, the way they did when they forgot Sam was in the room. "Can you remove the third place setting from that table?" he asked the host. "And maybe send over some candles or something?"

He sent Dean a text when he got back to the motel, so they wouldn't worry and go off on a crazy rescue mission for him (although now that he thought about it, that would probably be an awesome first date for Dean and Cas). Gone back to motel. Have fun, guys.

Sam spent the evening savouring the experience of being alone in the motel room without being in the middle of a fight with Dean, and catching up on some reading. He couldn't believe how long it had been since he'd last read a book for entertainment. The Impala rumbled into the parking lot just before midnight – easily late enough for them to have gone to a movie and then followed it up with 'other stuff'. Sam pulled back the curtain a couple of inches and peeked out.

Dean and Cas were standing very close together in the pool of light made by the bulb outside the motel room door, looking intently at each other. Kiss, kiss Sam chanted in his head.

They didn't. But Cas did put his hand on Dean's shoulder and leave it there for a minute, and Dean did tuck Cas's hair behind his ear, so Sam took it as a win.

Sam dropped the curtain and flung himself across the room so he was lying casually on his bed pretending to read when the door opened and Dean walked in alone.

"I hate you, Sam," Dean said, but Sam could hear the smile in his voice.

A/N: I hope you liked it. This was my attempt at writing a girl!Cas fic that wasn't really sexist and didn't make Cas OOC. Review and let me know what you think.

Disclaimer: Supernatural is not mine.