'How many nights have been like this?' Dean wondered. He thought for a minute before deciding the answer was 'too many'. He had thought it would be over after Azazel and the gates of Hell; after Lilith and the Apocalypse; Dick Roman and the Leviathan. Now this – it was a never-ending cycle. He shifted a bit in bed, too tired to get up, but not enough to sleep.
He knew Sam would be out cold, able to sleep through anything still. Dean thinks Castiel is probably still in the motel room, watching bad infomercials. It's become his ritual the night before anything big might happen and Dean just doesn't understand what the angel finds so fascinating about them.
Dean senses movement in the room and realizes he fell asleep for a short time. He assumes it's just Sam getting some water until he feels a weight on his bed. He quickly grabs his gun and turns to face whatever enemy has appeared.
"Cas?" he whispers once he realizes who he is pointing the gun at. Castiel holds a single finger to his lips and Dean puts the gun back under his pillow, a confused expression on his face. The angel shifts all of his weight onto the bed so he's lying next to the hunter before he takes Dean's hand in his own.
Dean's eyes widen at the contact and he must tense up because Cas turns to look at him, eyes worried. He doesn't let go of Dean's hand though. A million moments pass while they share their silent conversation. Dean notices at some point they both shifted so they are on their sides, facing each other. He isn't sure how that happened, but he's too tired to care finally.
When the man finally falls asleep, Castiel pulls the covers up a bit, his hand coming to rest on Dean's shoulder. Dean reacts to the touch in his sleep, grasping to make contact. He seems content when his arm drapes across the angel's waist and he falls back into the rhythmic breaths of deep sleep. Castiel doesn't move, for fear of waking the man. He just keeps watch over the Winchesters, as he always does and always will, come what may.