Castiel watched the exchange between Dean and Sam on the bridge. He saw the anger burning in Sam's eyes, just as he saw the guilt and despair in Dean's. He knew it would take longer for them to recover from this, and he supposed he understood why considering that Dean tricked Sam into letting an angel possess him. Dean knew it too, and Castiel could practically feel his former charge's heart drop from the increasing guilt.

Something changed slightly in Dean when Sam tried to blame Kevin's death on himself. It was barely noticeable, but Cas saw it. Going against his new-found morals on privacy, and also Dean's wishes, he peered into his friend's mind. What he saw in Dean's mind was horrifying, as were his words aloud that he was poison and needed to find and kill Gadreel on his own. When Dean began to walk off after Sam dismissed him, Castiel followed him all the way to the Impala.

Turning around, Dean noticed Cas standing there. "Cas, you have to stay with Sam in order to heal him. I don't like separating, either, especially after all of the times I had to send you away, but you have to stay." There was a slight rush of desperation in his voice, but Cas wasn't coming along with him. He just needed to talk, out of Sam's earshot.

"Dean, I understand why you think you need to leave. Bad things have happened around you, but that is not all on you. You are not poison, and you do not shorten the lifespan of those around you. Don't listen to Crowley. This is not your fault; Kevin is not your fault." When Castiel's words seemed to fall on deaf ears, he became desperate, and spoke aloud what he was trying to avoid. "Please, don't do this Dean. I know everything seems bad right now with the world and Sam right now, but he will forgive you. Don't leave him, you're the only family he has left. Please." The last word was barely a whisper, but Dean caught it loud and clear.

He didn't speak, but nodded his head slowly. Cas could see that he had put the thought out of his mind for the moment, and it was enough. Not wanting to make Sam suspicious, or to delay their getting out of the rain any longer, he quickly gave the man before him a tight hug and walked back towards Sam. Had he turned around, he would have noticed the tear that slipped from Dean's eye before he slid into the Impala.