When Dean finally catches up to Cas, Sam a step ahead of him, he really isn't expecting what he finds,

The smaller angel is being cradled by Cas, with Castiel's head bent low over him. The Wiener Hut uniform, once obnoxiously cheerful, is grimy and covered in Samandriel's blood. Cas is holding a bloodied angel blade and Dean has no doubt hat if the Impala was any color other than black as night, he'd see two giant wing-prints flaring out along her right side behind them.

"Cas!" Sam exclaims, pulling up short. "What the hell happened?"

And for a moment, Dean actually wants to punch him. To tell Sam to shut up and give Castiel a minute.

Because even though something serious clearly just went down, the way Cas is holding Samandriel makes his insides turn over and his mouth go dry.

He can remember holding Sammy the same way, years ago. It's become a distant memory, faded slightly by time and Hell and so many other things that have happened since, but that gut wrenching pain of holding your dead brother is something he'll never be able to truly forget.

Dean doesn't think he's ever seen this close to Cas's soul.

He's just about to tell Sam that they should back off, give the angel a minute, when Castiel raises his head.

The look on his face is ragged, torn. "He was compromised," he says, and his voice sounds frayed around the edges.

"He came at me. I killed him in self-defense."

Cas sounds off, lost. And Dean knows that this is something the angel will always carry around with him. Just like Dean carries his dad, and mom, and Sammy. Jo, and Ellen and Bobby… This will never go away.

With all of the crap Cas has been through. With everything he's done, and had to face… This is the thing that finally broke him.

Dean knows, because he's seen the same look on his own face late at night, reflected in the mirror of dozens of motel bathrooms.

Dean calls Benny the next day. Calls to tell him he won't be seeing him anymore.

And while it eats him up inside, makes him hate himself just a little bit more, he can't shake the image of Samandriel so small and helpless in Castiel's arms. And he knows, with a sudden fierceness, that he doesn't want Sam to go. He still needs him, just like he did back then, digging in the dirt at the crossroads. And Sammy needs him.

Thing is, Cas needs him too. Dean knows that now. He just has to figure out how to patch those torn and frayed edges back together somehow.