Castiel backed up, then surged forward to slam against the barrier. He crashed into it, pain shooting all up and down one side of his body. But he didn't care. He didn't care if he shattered himself against this invisible wall, he needed to get through. His friends needed him.

The Darkness had learned much in its eons of solitary captivity. It remembered that it had been God and his archangels that had managed to slam shut the gates. And it had learned how to lock its mortal enemies out.

Castiel didn't know why The Darkness had chosen this place in the middle of nowhere to nest. But it had protected it well against any assault that might come from Heaven. All angels were barred by an invisible barrier.

But two humans had gone through to face The Darkness alone.

Cas couldn't see the Winchesters from up here, flying high above the field. The area was warded from his sight or hearing. In desperation he threw himself at it again and again, but was unable to so much as dent the wall. He ignored the voices of his brothers and sisters, calling for him to come away, to let the Winchesters complete their mission if they could. To let them take on The Darkness alone.

Castiel simply couldn't abide that. If they were going to fight, then his place was beside them.

Suddenly, a blue-white light erupted from the ground far below. It pushed away The Darkness' wards. The barrier fell.

Castiel sped toward Earth, his heart hammering in his chest. The other angels called to him, told him to come back.

He didn't listen.

-o-

Castiel crashed down into the field.

The Darkness writhed and shrieked like a wounded animal behind a cage of light, its noise muted as its influence dissipated. Cas looked around, and saw a large shape lying near the middle of the field, at the light's epicenter. Cas took a hesitant step toward it, then another, his heart sinking with every step.

It was Sam.

A white sigil glowed from his chest, a gruesome stab wound marring his flesh, pierced through his too-good heart. His face was pale, but peaceful in death.

Castiel fell to his knees beside his friend.

"Oh, Sam," he whispered, his hands falling to his sides. Emotion swirled inside his chest, making it hard to breathe.

This was so wrong… He didn't deserve this…

A small sound reached Cas' ears, barely audible over The Darkness' struggling. It sounded like someone coughing.

He looked around for the source. When he saw a second shape lying not too far off, Cas jumped to his feet and ran over.

His sorrow nearly overwhelmed him when he took in the sight of Dean's broken body. His friend was still alive, barely clinging to life, most likely through sheer stubbornness. A deep slash in his stomach bled steadily, taking an excruciatingly long time to bleed out.

Castiel sank to the ground once more, pain constricting his throat and prickling his eyes. Gently, he gathered Dean into his arms and held him against his chest.

Dean opened his eyes. When he saw who held him, his battered face cracked into a smile.

"Cas?" he whispered.

Castiel met his gaze, tears threatening to spill over. "I'm here," he croaked.

"I'm sorry…"

"No, don't… You don't have to…"

"We wanted to tell you," Dean insisted, his green eyes pleading. Every word took an immense effort on his part. "We wanted to tell you…about the plan. But we knew…you would've stopped us."

"You were right," Cas said simply, fighting to keep his voice even. He looked at the light. "What is this?"

Dean took a breath to explain, but coughed wetly. He gasped in pain, his body shuddering involuntarily.

"It's OK, don't talk," Cas said quickly. He placed a hand on Dean's head and closed his eyes.

He saw into his friend's memories. A spell… a sigil branded onto their own flesh, right over their heart… two sacrifices required… the first would bind The Darkness… the second would vanquish it for good… The spell activates at the moment of death… As soon as Dean died, it would be complete…

Castiel gasped and opened his eyes. He gently nudged aside the collar of Dean's shirt, and saw the edge of a brand on his chest, the same symbol that glowed on Sam's.

Castiel no longer tried to stifle his tears. "Oh, Dean…"

"Cas… There was no other way…"

"But…"

"Listen to me," Dean whispered. "You did…everything you could…You saved our asses…so many times…It had to be…this way."

Castiel look at him, and saw tears pooling in Dean's eyes as well. So much horror those eyes had seen. He deserved to be free of it.

"Let me help you," Cas begged. He reached toward Dean's forehead with two fingers.

Dean jerked his head away and swallowed, grimacing. "No healing…The Darkness has to be the one to…to kill me, Cas…That's how the spell works…It's already…done…Just a little longer…"

"You don't have to suffer, Dean. Please." The last word came out as a sob.

Green eyes bored into blue, and suddenly Dean understood. He gave Cas another weak smile, and the tiniest of nods.

"Rest now, Dean," Cas whispered, reaching toward him again.

"See you soon, Cas," came the quiet reply.

The angel placed two fingers on the man's forehead, and Dean's eyes closed as he drifted off to gentle sleep.

Castiel held Dean as he slept, he didn't know how long. Tears dripped from his eyes as he sat, cradling his dearest friend in his arms as he died. Castiel felt so small and helpless. He'd been able to spare Dean from the terrible pain of his last moments, but it seemed like such a small gesture.

Dean's breath shuddered in his chest. Cas waited as he breathed in and out.

In.

Out.

In.

…Out…

And then there was nothing.

Cas sobbed, holding Dean's body against his chest as he cried. In all his thousands of years of existence, the angel had never felt such an overwhelming feeling of loss. It was as if a deep pit had yawned open in his gut, threatening to drown him in the sorrow that surged up inside.

A burst of light made Cas jump. The sigil burned into Dean's chest had activated. As Castiel watched, squinting against the brightness, it blossomed until it enveloped the entire field, just as Sam's had done. Then it began to slowly collapse, shrinking in on the incarcerated Darkness at its core.

The Darkness roared in fury, slamming against the walls of its prison, but the light would not budge. It collapsed further, searing The Darkness and pressing it smaller and smaller.

Then finally, with a final shriek and a loud bang, the light exploded.

When Castiel had blinked the bright spots from his vision and looked again, the light was gone, as was The Darkness. The field was once again steeped in natural moonlight and starlight.

The evil was defeated.

And the Winchesters were dead.

-o-

Castiel burned Sam and Dean's bodies together in that same field, the site of their greatest sacrifice. He stood vigil over their pyres as the flames flew higher and higher in the pale light of dawn.

For a long time he stayed in that field. His grief was so potent that it seemed to thrum through the air. Every angel in Heaven felt it surging across the airwaves. They had never felt anything like it, and they stood in silent awe of such powerful, humanlike emotion pouring out of one of their own.

Castiel stayed, unmoving, barely blinking, until the last cinder drifted to the ground. And then he turned and disappeared from the field, never to return to that place.

-o-

He returned the Impala to the bunker's garage. He could have carried it there, zapping it from one place to the next. It barely weighed an ounce to him, after all.

But for some reason that felt wrong.

Castiel didn't think Dean would mind if he drove it home for him.

-o-

Cas didn't touch any of Sam or Dean's things in their bedrooms. He wanted them to stay preserved exactly as they were.

He tidied up the kitchen – the boys probably would have laughed at the sight – and straightened the library.

He could have simply left it all. Cas could have locked the bunker tight and destroyed the only key. But he knew that's not what Sam and Dean would have wanted.

Instead, he decided to hold onto the key for now. Perhaps one day, other young hunters would prove themselves worthy of the legacy. Perhaps they would find this place and all the treasures within.

Perhaps they too would come to make this place their home.

And when they did, Castiel would make sure to come to them, and tell them the story of two brothers who sacrificed everything for a world that didn't even know their names.

-o-

Weary from travel and from grief, Castiel finally returned to Heaven, his tasks completed. He made his way down one of the many gleaming hallways, his feet heavy, but his heart growing lighter with every step. He stopped in front of a door,

pushed it open and stepped inside.

As he looked around the brightly lit room, comfortably quiet and warm, he couldn't help but smile.

So this is Dean's idea of Heaven…

"Dean?" Cas called.

A different door opened from the other side of the room. Castiel barely recognized the man who stepped through.

Dean looked better than he had in years. The perpetual shadows under his eyes were gone. The years of compounding injury upon injury had vanished. A lifetime's worth of grief and anger had gone, taking with it a massive weight off his shoulders. He looked… content.

Dean smiled warmly, crossing the room to pull Cas into a tight hug, which Cas gladly returned. Dean clapped him on the back before they pulled apart.

"It's good to see you, Dean," Cas said, smiling tiredly. "You look well."

"You, on the other hand, look like crap," Dean replied. "Come in, man."

Castiel followed Dean into the other room. Inside were shelves upon shelves of books, more books that anyone could hope to read in any number of lifetimes. Cas couldn't help but grin; he should have guessed Sam's heaven, which adjoined Dean's, would contain at least one library.

Sam stood up from the table where he had been reading from a leather-bound volume nearly as big as he was. He laughed and gave Cas a hug.

The three of them stood in comfortable silence for a moment, Cas looking around the library.

"Welcome to nerd-vana," Dean quipped. Sam made a face at him.

"Are you both… all right?" Castiel asked.

The brothers traded glances.

"Yeah, Cas," Sam assured him gently. "We're OK."

"I'm so sorry… The Darkness…," Cas began.

"Is gone," Dean finished for him. "It was worth it."

"Definitely," Sam agreed.

Castiel shook his head, blinking back tears.

Dean placed a hand on his shoulder. "Cas… It was always going to end bloody for us," Dean said quietly.

"And anyway, we're here now," Sam added with a small smile. "Nothing really ends."

Cas nodded and cleared his throat. "After everything you've done, all the lives you've saved… You can go wherever you'd like, visit any other heaven you want. If you ever need anything, anything at all, you have only to ask. All of Heaven is in your debt."

Dean smirked. "You pull some strings for us with upper management?"

Cas smiled. "Something like that. And I have an idea for where to start."

-o-

Cas held the door open, ushering the boys inside. They stepped into a warmly lit foyer of a quaint little house. A familiar one.

They turned back to look at Cas, who smiled to himself.

"Cas, is this…?" Sam asked quietly. Dean's eyes were bright.

Cas nodded.

A thump of footsteps sounded from the living room to the left. The boys turned, startled.

A dark-haired, grizzled man rushed to the doorway and froze when he saw who was there.

The three men stared at each other, open-mouthed.

"Dad…" Dean whispered.

John Winchester took in the sight of his sons, emotion welling up in his face. Tentatively he stepped toward them. Then he crossed the distance between them in two long strides and pulled both of his boys into a hug.

Sam and Dean wrapped their arms around their father, gripping the back of his shirt as the three of them stood there, holding each other silently. It was a long time before they pulled away.

"I'm so proud of you boys," John croaked, tears glistening in his eyes.

More footsteps sounded on the stairs behind them. Sam and Dean turned to look who else was there.

Mary Winchester stopped at the top of the stairs, one hand covering her mouth.

"Dean…," she whispered. "Sammy…"

With shaky knees she descended the steps. She stopped in front of both of her sons, placing warms hands on their faces and looking each of them over, drinking them in with all her love shining in her eyes.

The whole family cried as Mary hugged both of her boys. Castiel watched as they seemed to melt into her arms, too many long years having separated them until now.

Still smiling, Cas turned and quietly showed himself out. He would give them some time alone to catch up and just be together, after so much time and so many terrible trials.

Sam and Dean deserved peace. Their work was done.

At long last, the Winchester brothers were finally… finally

Home.