So, I've started writing fics again. I was going to work on some other RL things, but this story has just taken hold of me.

Note: This story takes place at the very end of the series when they are closing the Gates of Hell. So, the first chapter picks up right as the Gates are closing, and the rest of the story deals with the aftermath.

Disclaimer: I own nothing related to Supernatural. The only thing I own is the story idea.

Cas knew. He had known for a long time, but no one had really called him out on it before.

But there was this boy—this prophet—who of course could see right through him.

Kevin Tran had been staring at him for some time. At first, Cas had not thought much of it. After all, they were both stuck in the back seat, and the Winchesters were doing that thing.

Dean called it preparation. Cas called it barely concealed panic.

The brothers had hardly spoken a word to each other. Dean turned the music on so loud that Cas knew conversation would be difficult using Jimmy's vocal chords. Not that he wanted—or needed—to talk to anyone. There had been plenty of talking before: about Naomi, about Heaven, about Crowley, about Hell.

But it had been a full thirty minutes now, and Kevin just kept staring at him.

Cas was quite certain that Kevin knew the truth. How could he not? He read the tablet, and he was giving the Winchesters instructions. But Cas could see behind this kid's eyes that he knew what this would mean. Which was probably why he kept staring at Cas.

He could still hear Naomi. They would never go through with it if they knew. And now he knew, but he would never tell them. Not until after.

"I think we should go to Vegas when all this is over," Dean said suddenly. He reached over to turn the music down just enough so that Sam could be heard, but Cas and Kevin would have to struggle.

"If we survive that long," Kevin said through his teeth. He was being particularly negative, but Dean said that was because Kevin's mom was elsewhere helping Garth run the distraction campaign. (Cas could believe that; he had met the woman, and she was as fierce as an archangel.)

Dean glared at Kevin in the rearview mirror. "When this is over," he said sharply, "Sam's taking you to Disneyworld."

"And leaving you there," Sam said, just loud enough that Cas could hear but not Kevin.

"I'm not twelve," Kevin said.

"Right," Dean said. He was smiling again, that weird smile that he did when he worked with anyone under age twenty. Cas liked that smile; it was not forced.

Cas knew why the brothers were talking again. He could see the church just ahead. The Impala was slowing down. Black smoke filled the air, and Cas could feel the hairs on the back of his neck standing up with the electricity of it all.

It hurt. He had never told the Winchesters that, but it hurt to be around so much evil. There was a kind of energy that came with being a demon. That was what the black smoke was, really—a physical manifestation of that energy. And it was like placing magnets next to each other. The energies repelled each other. Cas had always had a harder time fighting demons than anything else, but that was his job. When he was still a soldier, he fought demons because he had to. When he became a hunter, he fought them because he needed to. And soon, he would fight them because they would be trapped on this side of Hell when the doors closed. That didn't mean it didn't hurt; it just meant he got used to the hurt.

But the good part about the hurt? He knew exactly how many of them there were. He could feel that much power pushing back against the purer energy that was his grace. So, when he told Dean that there were two hundred and seven demons, that was exact, and he was confident in it.

Well, two hundred and eight. But he wasn't counting Crowley.

Dean turned the keys and opened the door to the Impala. Sam was close behind, and Cas had already transported himself out of the car. Kevin was having trouble. When Dean fixed up the Impala after the last clash with the angels, one of the replacement doors had a child safety lock.

Crowley inclined his head to look at Kevin, then looked back up at the Winchesters. "Hello, boys," he said. It was his usual greeting. He hardly looked at Cas. Once, they had been the bitterest of enemies. Now, Cas was swallowed up in the "Winchester associated" enemies section, especially after Naomi. Cas didn't mind being a lesser threat, though. The Winchesters were plenty to be reckoned with, and he didn't like to think there was a competition.

"Skip the pansy pleasantries, Crowley."

"Straight to the part where I kill you, then?"

"You can try," Dean said. He thrust his jaw forward—a nervous habit. He did it when he wanted to look bigger and distract them from the fact that he was still very much just a human.

And then there was black smoke everywhere. It pressed in around them, but mostly around the boys. Cas kept his arms around Kevin, even wrapping his wings around them both.

Stick to the plan. Stick to the plan. The Winchesters can hold their own. Stick to the plan.

He was practically carrying Kevin now. Every step he took was surprisingly easier. He could feel the power coursing through him, the power Naomi had promised. Heaven was ready to see the gates close, and Cas was the battery to make it happen. Of course he was. Who else could they have picked, considering?

"Sam!" he heard Dean shout. Cas reminded himself not to look. Stick to the plan. Besides, that was Dean's lost cry. He couldn't see his brother; that was it. There was a different cry entirely for when Sam was in trouble. That one was much worse.

"Dean!" came the response. At least they had found each other. But they sounded hoarse. Maybe he should go back and help them.

"Stick to the plan," Kevin Tran said. And he was right, of course. Dean must have said it a hundred times, and Cas was good at obeying orders—well, orders that were right—but this time was different. What if there was no after?

But he had tried to say goodbye before, in Purgatory. He wasn't very good at it.

There was light pulsing all around him—no, light pulsing from inside him, too. He could feel it: the grace of a thousand angels being poured inside him. Heaven wanted the gates closed, and he was the power source on Earth. There were no other angels around to do it; they had all returned to Heaven. They had to.

He tried not to think about it too much.

The demons could hardly touch him. He imagined this is what it felt like for the archangels. All this power. He could see how they would want to wield it. But he remembered the last time he had this much power, so he tried not to use too much of it until it was time. He remembered the Leviathons.

He kept his wings wrapped around Kevin. He had killed most of the archangels, after all, and so there was a little less protection for the little prophet. Heaven figured he could take care of it. Castiel, the basically-fallen angel. Protector of the Prophet and Friend of the Winchesters. Also occasionally Spy and Traitor and Genocidal Maniac. But sometimes Dean liked to pretend he didn't have those last titles. Unless he was mad. Or drunk. Or both.

Kevin Tran was shaking. He had been a prophet for four years now and still he was shaking under pressure. Cas held him tighter, because that was what Dean did for kids he saved, and it seemed to work. Kevin told him he was crushing him, though, so that didn't work.

"Think now's a good time?" Kevin asked. He did not look at Cas when he asked the question, not because he was scared, but because Cas was brighter than human eyes could handle now. This, of course, helped with the demon problem, but it made holding all that power in an issue.

"Now or never," he said. Already he was full to the brim, bursting with energy—so much energy that even just breathing required that he let off a little steam. A demon or two got vaporized just with that energy. That was good. He was tempted to breathe a little heavier and see if he could vaporize the ones nearest the Winchesters.

But, no. He was supposed to stick to the plan.

Kevin started the incantation. He pulled the ingredients out of his pockets. It had taken Cas a month to get all those things—he had been gone from the Winchesters for far longer than he or Heaven was comfortable with. And now Kevin Tran was about to light a month's worth of work on fire.

Crowley tried to stop him, of course. Once he realized that Kevin and Cas were the problem and not the Winchesters—though, of course, how could he even think that the Winchesters were not the main problem when he had their entire lifetimes' worth of experience to go on—he let out a shriek that would have pierced Kevin's eardrums if Cas had not been shielding him.

Cas stood up straighter. He let his wings expand. He let the light that was already blinding Jimmy's senses shine through those feathers. There was only the Crowley loose end to tie up. He and Kevin both knew that Crowley, of all the demons there, could stay on Earth if he wanted to. The King of Hell and all. "Decide," he said, and the voice that came out was so booming and deep that Kevin let out a cry of surprise and covered his ears. "You can stay here and be much less powerful, cut off from your source of power, or you can go back and be the king of your own little world." It sounded so good when he said it with that voice, not at all like he had been rehearsing it. Dean had a thing about witty retorts, and he had been working on sounding "awesome."

"You haven't got the juice," Crowley said, but the look in his eyes . . . . He knew.

"Castiel," Kevin said. He was ready. He held out the pieces of the spell. The bowl was flaming now. They just needed some serious power to weld them together. Cas reached for them, Crowley reached for Cas, and the mixture of dark and light exploded into color. He barely had time to shove Kevin Tran to the ground before the light and energy was pouring out of him.

Well, it was too late to stop it now.