Spoilers to 8.17 'Goodbye Stranger.'

Sitting in the back of the Impala, holding a towel to his bleeding bullet wound, Cas almost wished he was still laying in the dark road.

Dean shouted at him, of course, yelling at him for everything he did that night he ran away with the angel tablet. He demanded an explanation but refused to accept anything Cas said, and Cas just gave up.

"I'm sorry." The angel said vehemently for the hundredth time, breaking the heavy silence that had formed once Dean had shouted himself hoarse. Dean didn't say anything. He was ignoring him now.

Cas sighed. Then he realized something. "Where-where's Meg?"

Sam glanced at Dean, who spared his brother a worried look but still refused to talk to Cas.

"I said where's Meg?" Cas repeated, louder, when he didn't get an answer.

Sam sighed. "I'm sorry Cas."

"What do you mean you're sorry?" Cas almost laughed, trying his hardest not to think anything bad happened to her. She was just hiding somewhere safe. Wherever the Winchesters were taking him. She would be there.

"Meg didn't make it. She offered to hold Crowley off when he showed up that night, and we saw him stab her right as we were leaving." Sam informed him sadly.

There was a few moments of silence in which Cas took the news in. "You said you would protect her." He eventually said to Sam, his voice cracking.

Sam sighed again. "I know. But she wanted to save you and I couldn't do anything to stop her."

Cas felt like the insides of his vessel were lead. "She thought she was saving me when really I left you guys there. I could've went back and saved her if I had stayed. This is all my fault." He felt tears on his cheeks but he didn't remember when he started crying. "It's all my fault that Meg is dead."

Neither of the Winchesters said anything, which didn't help him feel any better. Not wanting to talk anymore, he turned his head so he was looking out the window. He didn't feel the bullet wound anymore. He didn't feel anything but numb, emotional pain.

"I'm so sorry Meg." He whispered to the darkness beyond the car.

Then he closed his eyes and tried to remember better times.