Dean and Castiel ran toward the Impala, the demons hot on their heels. Sam was not far away, fighting off more of them with the demon-knife. Dean wrenched open the back door of the Impala and chucked the case they had just stolen into the backseat before diving in after it. He could see the flash of light from Cas smiting a demon reflected in the window. He pulled his rock salt loaded shotgun from his belt and turned around as Cas tumbled clumsily backward into the Impala. A demon charged at the open car door and Dean blasted it full of rock salt, send her reeling backwards in pain. Dean stretched over Cas and reached for the door handle.
"Sammy! Hurry up and get our asses outta here!" he shouted, then slammed the door.
Dean sat back and sighed in relief, glancing at the case they had stolen.
"That was a close one, wasn't it, Cas?" he said, turning to the angel. "Cas?!"
Dean's breath caught in his throat. The silver handle of an angel-blade protruded from Castiel's chest, blood spreading across his trench coat, and a glimmer of white light shining from the wound.
"No! Cas, hang on, buddy, we can fix this. It's gonna be okay," Dean said.
He gripped Cas tightly and pulled him closer into his arms. Cas's breathing was shallow and he was trembling in pain.
"Dean," he said weakly. "There's nothing you can do. It's too late."
"No it's not. Look, it's not so bad, we can patch you up in no time," Dean said.
He gently placed a hand near the wound and felt his stomach knot up as he realized just how close to Castiel's heart the blade had pierced.
"Cas, come on, please stay with me."
He leaned forward and kissed Cas softly on the lips. Pulling away, he saw a small, sad smile playing on the angel's face.
"Please, I'm begging you. Don't leave me," Dean whispered.
"I can't just decide not to die, Dean," said Cas. "You of all people should know that."
A tear fell from Dean's eye and landed on Cas's cheek, mingling with his own tears. Cas was horribly pale now and the light from his wound was shining brighter by the moment.
"Cas, please," Dean begged one more time.
Cas looked up at him, his bright blue eyes filled with pain.
"I'm sorry, Dean," he whispered.
Then there was an explosion of light. But Dean didn't look away, even though it felt like the light would blind him. A white-hot pain seared across his arms, but he just gripped Cas tighter. Finally, the light faded away.
The front door of the Impala suddenly slammed. It was Sam.
"Let's get the hell out of here," he said, revving the engine to life, but Dean hardly heard him.
Sam swung the car around and raced out of the parking lot. He didn't even seem to have noticed the scene in the backseat. It wasn't until they reached the cabin they were hiding out in that he turned around.
"Okay, guys, let's get in and see if that case was worth the trouble," said Sam. "Dean? Cas?" he said when no one answered.
He frowned and turned slightly, noticing something odd and black on the dashboard out of the corner of his eye. Slowly he turned, following the smoky black imprint of an angel's wing, stretching into the backseat where Castiel lay, gripped tightly in Dean's arms.
"Oh my God," gasped Sam.
Castiel's wings weren't just scorched into the Impala. Looking at Dean, Sam saw that the black feathers were scorched across his brother's arms. Sam didn't need to ask to know that Dean would bear those marks for the rest of his life. Dean was still clinging desperately to Cas, tears falling freely.

Night had fallen. The moon cast a mournful light on the forest where Sam and Dean stood beside the funeral pyre. Dean had insisted on giving Cas a hunter's burial.
"He was one of us in the end," he had said.
Sam pulled a lighter from his pocket and lit the torch.
"Do you want to do it?" he asked quietly.
"Give me a moment," Dean said.
He stepped forward to the edge of the pyre and pulled the sheet back from over Castiel's head, staring long and hard at the angel's face. It seemed even more deathly pale now in contrast with his dark hair.
"Bye, Cas," he whispered.
He ran his hand through Cas's hair and kissed him lightly. Then he replaced the sheet over his head and took a step back. He took the torch from Sam and set the pyre in flames, only hesitating a moment. He didn't take his eyes off the veiled figure of Castiel as he fell back into line with Sam. After a little while, Sam went back into the cabin. But Dean stayed beside the pyre until the embers went cold.