It happens so fast it almost knocks him down. As soon as Dean and Sam break the door of the hide out, Dean is blinded by a hot white light, and feels more than hears a high-pitched tone. His knees buckle, and something flickers in the back of his mind, then it's like a dam breaking in his head. Coming out of Hell. The light. The sound. "CAS!" Sam is next to him, yelling some curse.
Suddenly it's over. And there is holy, perfect, strange Castiel, angel of the lord, confused and relieved. He nods, "Hello Dean. Sam," some intense look of gratefulness in his ageless eyes.
"Hey-" Dean can't finish before he's explaining, "I'm sorry. This place allows me in with your presence, and I had to escape as quickly as possible, and without my vessel I'm technically a wavelength many times faster than light… Do you remember now? It was probably buried further in your subconscious memories, but your prayers were so loud they let me find you and get in immediately. Do you know me?"
Castiel steps toward Dean, tilting his head up in hope. Dean doesn't understand at all yet. And he can't care now.
"Cas," tears of relief and shock threatening, "Are you… I…" And if he's already standing weakly in front of the angel, reaching out to touch his shoulder, his strange and unmarred face, Cas doesn't seem to mind.
"Yes, Dean, I'm…I'm here now. You saved me. Brought me back." Castiel doesn't hesitate in taking Dean's shaking hand and holding it to his own face, kissing the palm lightly. "It's ok. I'll explain…"
And that's the end of words because Dean is planting his other hand on Castiel's face and dragging him with all of his strength into a hard kiss of fierceness, apology, relief, shock, and, yes, love. One of Cas's hands threads timidly in Dean's short hair, the other covering the mark on the shoulder he'd gripped and loved, been tortured for. It's all worth it, all ok now.
And Sam will never tell either of them about the tears spilling over his smile as he walks into the next room.